diff --git a/CHANGELOG.md b/CHANGELOG.md
index c22aa56..9cc4b71 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,19 @@
 
 本文件记录 `ShrinkEventBus` 在当前工作区中的包内变更。
 
+## [2.3.0] - 2026-11-06
+
+### Added
+
+- 新增 `EventBus.PostDeferred(bus, event)`，把 MainThread Bus 的事件推迟到下一次主线程泵送；重入发布不会在同一次泵送中立即执行。
+- 新增公开的 `EventBus.ObserveDiagnostics(...)` 与 `ShrinkEventDiagnostic`，供编辑器和外部工具读取分发时间、Bus、调度器、线程、耗时、结果与同步标记，不再依赖私有事件或反射。
+- `ShrinkPostFailure` 新增 `DeferredUnsupported`，用于 `Inline`、`DedicatedThread`、`TaskPool` 或宿主没有延后派发能力的情况。
+
+### Changed
+
+- Runtime Abstractions 0.2.0 新增 `IShrinkDeferredMainThreadDispatcher`；Unity PlayerLoop 与共享 `SynchronizationContext` 调度器实现该接口。
+- 诊断观察者逐个隔离异常，单个观察者失败不会阻断业务 handler 或其他观察者。
+
 ## [2.2.3] - 2026-10-03
 
 - Unity 可独立通过 Git URL 安装，必装依赖仅保留 UniTask 和官方 Mono.Cecil。
diff --git a/DotNet~/ShrinkSDK.EventBus.csproj b/DotNet~/ShrinkSDK.EventBus.csproj
index 67c10a5..d54d74a 100644
--- a/DotNet~/ShrinkSDK.EventBus.csproj
+++ b/DotNet~/ShrinkSDK.EventBus.csproj
@@ -5,7 +5,7 @@
     <AssemblyName>ShrinkEventBus.Runtime</AssemblyName>
     <RootNamespace>ShrinkEventBus</RootNamespace>
     <PackageId>ShrinkSDK.EventBus</PackageId>
-    <Version>2.2.2</Version>
+    <Version>2.3.1</Version>
     <Description>ShrinkSDK typed event bus runtime.</Description>
     <ShrinkCodeGenEnabled>false</ShrinkCodeGenEnabled>
   </PropertyGroup>
@@ -14,6 +14,6 @@
              Exclude="..\Runtime\ShrinkMonoEventScope.cs" />
     <PackageReference Include="UniTask" Version="2.5.10" />
     <PackageReference Include="ShrinkSDK.CodeGen" Version="0.2.0" PrivateAssets="compile;runtime;contentfiles;native" />
-    <PackageReference Include="ShrinkSDK.Runtime.Abstractions" Version="0.1.0" />
+    <PackageReference Include="ShrinkSDK.Runtime.Abstractions" Version="0.2.0" />
   </ItemGroup>
 </Project>
diff --git a/README.md b/README.md
index 673e7e5..d5af685 100644
--- a/README.md
+++ b/README.md
@@ -20,7 +20,7 @@ https://github.com/cneicy/ShrinkEventBus.git
 | 已安装的共享包 | 行为 |
 |---|---|
 | 无 | 使用包内调度接口和 EventBus 专用 ILPostProcessor |
-| Runtime Abstractions 0.1.0+ | 额外启用共享主线程调度器适配程序集 |
+| Runtime Abstractions 0.2.0+ | 额外启用共享主线程调度器适配程序集，并支持显式延后发布 |
 | Shared CodeGen 0.2.1+ | 停用包内织入，交给共享 CodeGen 统一生成订阅 |
 | 两者都有 | 同时启用上述两项集成 |
 
@@ -199,6 +199,29 @@ Burst Job 只写 unmanaged 事实事件到 NativeQueue；Playback 在托管/ECS
 
 `ShrinkBusOptions` 配置队列容量、溢出策略、最大并发、关闭排空和超时。关键业务默认使用 `Reject`；`DropNewest/DropOldest` 只适用于明确允许丢失的数据；`Wait` 只由 `PostAsync` 使用。
 
+## 延后发布与诊断
+
+MainThread Bus 可以用 `PostDeferred` 把事件推迟到下一次主线程泵送：
+
+```csharp
+var result = EventBus.PostDeferred(gameBus, new PlayerReadyEvent());
+if (!result.Accepted)
+    Debug.LogWarning($"deferred post rejected: {result.Failure}");
+```
+
+延后发布只接受 `MainThread` 调度且宿主实现了 `IShrinkDeferredMainThreadDispatcher` 的 Bus；其他调度器返回 `DeferredUnsupported`，不会退化成同步分发。队列仍遵守 `QueueCapacity` 与 `OverflowPolicy`，重入发布的事件留到下一次泵送。
+
+需要外部工具观察分发时使用公开诊断订阅：
+
+```csharp
+using var subscription = EventBus.ObserveDiagnostics(diagnostic =>
+{
+    Debug.Log($"{diagnostic.BusKey} {diagnostic.EventType.Name} {diagnostic.Result.Failure}");
+});
+```
+
+`ShrinkEventDiagnostic` 提供时间、事件类型、Bus、调度器、分发模式、线程、耗时、发布结果和同步标记，不暴露事件对象。观察者抛出的异常会记录并隔离，不影响业务分发或其他观察者。
+
 ## UI Toolkit 调试器
 
 菜单：`ShrinkSDK/事件总线/事件查看器`。
@@ -207,6 +230,8 @@ Burst Job 只写 unmanaged 事实事件到 NativeQueue；Playback 在托管/ECS
 
 它只观察静态 `EventBus` 宿主管理的 Bus，不捕获独立 `ShrinkEventBusHost`；性能基准仍使用独立 Host，避免 UI 采样进入被测热路径。
 
+Godot 项目安装 `ShrinkSDK.EventBus.Godot` 后可在编辑器中使用同一套诊断数据的独立调试窗口。
+
 ## Benchmark
 
 实现位于 `Benchmark/ShrinkEventBusBenchmark.cs`，入口：
diff --git a/Runtime/EventBus.cs b/Runtime/EventBus.cs
index caea5f3..0b3f4b3 100644
--- a/Runtime/EventBus.cs
+++ b/Runtime/EventBus.cs
@@ -133,6 +133,30 @@ namespace ShrinkEventBus
             CancellationToken cancellationToken = default)
             where TEvent : IShrinkEvent => DefaultBus.PostAsync(eventData, cancellationToken);
 
+        public static ShrinkPostResult PostDeferred<TEvent>(IShrinkEventBus bus, TEvent eventData)
+            where TEvent : IShrinkEvent
+        {
+            if (bus == null)
+                throw new ArgumentNullException(nameof(bus));
+            return bus is ShrinkEventBusInstance instance
+                ? instance.PostDeferred(in eventData)
+                : ShrinkPostResult.Rejected(ShrinkPostFailure.DeferredUnsupported);
+        }
+
+        public static IDisposable ObserveDiagnostics(Action<ShrinkEventDiagnostic> observer)
+        {
+            if (observer == null)
+                throw new ArgumentNullException(nameof(observer));
+
+            void Handler(ShrinkEventTrace trace) => observer(new ShrinkEventDiagnostic(
+                trace.TimestampUtc, trace.EventType, trace.BusKey, trace.Scheduler,
+                trace.DispatchMode, trace.ThreadId, trace.ElapsedTimestampTicks,
+                trace.Result, trace.IsAsync));
+
+            DetailedPosted += Handler;
+            return new DiagnosticSubscription(Handler);
+        }
+
         public static IDisposable Attach(object target, ShrinkBusKey? defaultBus = null)
         {
             if (target == null)
@@ -191,17 +215,38 @@ namespace ShrinkEventBus
             var observers = Volatile.Read(ref _detailedPosted);
             if (observers == null)
                 return;
-            try
-            {
-                observers(trace);
-            }
-            catch (Exception exception)
+            var invocationList = observers.GetInvocationList();
+            for (var i = 0; i < invocationList.Length; i++)
             {
+                try
+                {
+                    ((Action<ShrinkEventTrace>)invocationList[i])(trace);
+                }
+                catch (Exception exception)
+                {
 #if UNITY_5_3_OR_NEWER
-                UnityEngine.Debug.LogException(exception);
+                    UnityEngine.Debug.LogException(exception);
 #else
-                System.Diagnostics.Trace.TraceError(exception.ToString());
+                    System.Diagnostics.Trace.TraceError(exception.ToString());
 #endif
+                }
+            }
+        }
+
+        private sealed class DiagnosticSubscription : IDisposable
+        {
+            private Action<ShrinkEventTrace>? _handler;
+
+            public DiagnosticSubscription(Action<ShrinkEventTrace> handler)
+            {
+                _handler = handler;
+            }
+
+            public void Dispose()
+            {
+                var handler = Interlocked.Exchange(ref _handler, null);
+                if (handler != null)
+                    DetailedPosted -= handler;
             }
         }
     }
diff --git a/Runtime/ShrinkBusSchedulers.cs b/Runtime/ShrinkBusSchedulers.cs
index 5435d5b..98dcb15 100644
--- a/Runtime/ShrinkBusSchedulers.cs
+++ b/Runtime/ShrinkBusSchedulers.cs
@@ -1,6 +1,7 @@
 #nullable enable
 
 using System;
+using System.Buffers;
 using System.Collections.Concurrent;
 using System.Diagnostics;
 using System.Threading;
@@ -17,11 +18,22 @@ namespace ShrinkEventBus
     internal interface IShrinkBusScheduler : IDisposable
     {
         bool IsOnSchedulerThread { get; }
+        bool SupportsDeferred { get; }
         bool TryPost(Action action);
+        ShrinkDeferredPostStatus TryPostDeferred(Action action);
         UniTask PostAsync(Func<UniTask> action, CancellationToken cancellationToken);
         UniTask ShutdownAsync(bool drain, TimeSpan timeout);
     }
 
+    internal enum ShrinkDeferredPostStatus
+    {
+        Accepted,
+        QueueFull,
+        SchedulerRejected,
+        Unsupported,
+        Stopped
+    }
+
     internal sealed class ShrinkQueueFullException : InvalidOperationException
     {
         public ShrinkQueueFullException(string schedulerName)
@@ -81,6 +93,7 @@ namespace ShrinkEventBus
         }
 
         public bool IsEmpty => _queue.IsEmpty;
+        public int Count => _queue.Count;
 
         public bool TryEnqueue(ShrinkSchedulerWorkItem item)
         {
@@ -192,6 +205,7 @@ namespace ShrinkEventBus
     internal sealed class ShrinkInlineScheduler : IShrinkBusScheduler
     {
         public bool IsOnSchedulerThread => true;
+        public bool SupportsDeferred => false;
 
         public bool TryPost(Action action)
         {
@@ -199,6 +213,9 @@ namespace ShrinkEventBus
             return true;
         }
 
+        public ShrinkDeferredPostStatus TryPostDeferred(Action action) =>
+            ShrinkDeferredPostStatus.Unsupported;
+
         public UniTask PostAsync(Func<UniTask> action, CancellationToken cancellationToken)
         {
             cancellationToken.ThrowIfCancellationRequested();
@@ -213,36 +230,53 @@ namespace ShrinkEventBus
     {
         private readonly ShrinkSchedulerQueue _queue;
         private readonly MainThreadDispatcherContract _dispatcher;
+        private readonly ShrinkSDK.Runtime.IShrinkDeferredMainThreadDispatcher? _deferredDispatcher;
+        private readonly object _gate = new();
         private int _pumpScheduled;
         private int _disposed;
+        private bool _discardPending;
 
         public ShrinkMainThreadScheduler(string name, ShrinkBusOptions options)
         {
             _queue = new ShrinkSchedulerQueue(name, options);
             _dispatcher = ShrinkEventBusRuntime.MainThreadDispatcher;
+            _deferredDispatcher = _dispatcher as ShrinkSDK.Runtime.IShrinkDeferredMainThreadDispatcher;
         }
 
         public bool IsOnSchedulerThread => _dispatcher.IsMainThread;
+        public bool SupportsDeferred => _deferredDispatcher != null;
 
         public bool TryPost(Action action)
         {
-            if (Volatile.Read(ref _disposed) != 0)
-                return false;
+            if (Volatile.Read(ref _disposed) != 0) return false;
             if (IsOnSchedulerThread)
             {
                 action();
                 return true;
             }
+            return Enqueue(action) == ShrinkDeferredPostStatus.Accepted;
+        }
 
-            var item = new ShrinkSchedulerWorkItem(() =>
+        public ShrinkDeferredPostStatus TryPostDeferred(Action action)
+        {
+            if (action == null) throw new ArgumentNullException(nameof(action));
+            if (_deferredDispatcher == null) return ShrinkDeferredPostStatus.Unsupported;
+            return Enqueue(action);
+        }
+
+        private ShrinkDeferredPostStatus Enqueue(Action action)
+        {
+            lock (_gate)
             {
-                action();
-                return UniTask.CompletedTask;
-            }, awaitable: false);
-            if (!_queue.TryEnqueue(item))
-                return false;
-            SchedulePump();
-            return true;
+                if (_disposed != 0) return ShrinkDeferredPostStatus.Stopped;
+                var item = new ShrinkSchedulerWorkItem(() =>
+                {
+                    action();
+                    return UniTask.CompletedTask;
+                }, awaitable: false);
+                if (!_queue.TryEnqueue(item)) return ShrinkDeferredPostStatus.QueueFull;
+                return SchedulePump() ? ShrinkDeferredPostStatus.Accepted : ShrinkDeferredPostStatus.SchedulerRejected;
+            }
         }
 
         public async UniTask PostAsync(Func<UniTask> action, CancellationToken cancellationToken)
@@ -255,19 +289,24 @@ namespace ShrinkEventBus
                 await action();
                 return;
             }
-
             var item = new ShrinkSchedulerWorkItem(action, awaitable: true);
             await _queue.EnqueueAsync(item, cancellationToken);
-            SchedulePump();
+            lock (_gate)
+            {
+                if (_disposed != 0) _queue.DropPending();
+                else SchedulePump();
+            }
             await item.Completion.AttachExternalCancellation(cancellationToken);
         }
 
         public async UniTask ShutdownAsync(bool drain, TimeSpan timeout)
         {
-            Interlocked.Exchange(ref _disposed, 1);
-            if (!drain)
-                _queue.DropPending();
-            else
+            lock (_gate)
+            {
+                _disposed = 1;
+                if (!drain) { _discardPending = true; _queue.DropPending(); }
+            }
+            if (drain)
                 await ShrinkSchedulerShutdown.WaitUntilDrainedAsync(
                     _queue, () => Volatile.Read(ref _pumpScheduled) != 0, timeout);
             _queue.Dispose();
@@ -275,34 +314,66 @@ namespace ShrinkEventBus
 
         public void Dispose()
         {
-            if (Interlocked.Exchange(ref _disposed, 1) != 0)
-                return;
-            _queue.Dispose();
+            lock (_gate)
+            {
+                if (_disposed != 0) return;
+                _disposed = 1;
+                _discardPending = true;
+                _queue.Dispose();
+            }
         }
 
-        private void SchedulePump()
+        // All queued work shares one FIFO and capacity. Prefer the deferred dispatcher
+        // so a normal worker-thread post cannot pull deferred events into an inline pump.
+        private bool SchedulePump()
         {
-            if (Interlocked.Exchange(ref _pumpScheduled, 1) != 0)
-                return;
-            if (_dispatcher.TryPost(() => PumpAsync().Forget()))
-                return;
-            Interlocked.Exchange(ref _pumpScheduled, 0);
-            ShrinkEventDiagnostics.LogException(new InvalidOperationException(
-                "The configured main-thread dispatcher rejected an EventBus pump."));
+            if (_pumpScheduled != 0) return true;
+            _pumpScheduled = 1;
+            bool accepted;
+            try
+            {
+                accepted = _deferredDispatcher != null
+                    ? _deferredDispatcher.TryPostDeferred(() => PumpAsync().Forget())
+                    : _dispatcher.TryPost(() => PumpAsync().Forget());
+            }
+            catch
+            {
+                _pumpScheduled = 0;
+                _queue.DropPending();
+                throw;
+            }
+            if (accepted) return true;
+            _pumpScheduled = 0;
+            _queue.DropPending();
+            return false;
         }
 
         private async UniTask PumpAsync()
         {
+            ShrinkSchedulerWorkItem[] batch;
+            var count = 0;
+            lock (_gate)
+            {
+                var capacity = _queue.Count;
+                batch = ArrayPool<ShrinkSchedulerWorkItem>.Shared.Rent(Math.Max(1, capacity));
+                while (count < capacity && _queue.TryDequeue(out var item)) batch[count++] = item;
+            }
             try
             {
-                while (_queue.TryDequeue(out var item))
-                    await ShrinkSchedulerWorkItemRunner.RunAsync(item);
+                for (var i = 0; i < count; i++)
+                {
+                    if (_discardPending) batch[i].Drop(nameof(ShrinkMainThreadScheduler));
+                    else await ShrinkSchedulerWorkItemRunner.RunAsync(batch[i]);
+                }
             }
             finally
             {
-                Interlocked.Exchange(ref _pumpScheduled, 0);
-                if (!_queue.IsEmpty && Volatile.Read(ref _disposed) == 0)
-                    SchedulePump();
+                ArrayPool<ShrinkSchedulerWorkItem>.Shared.Return(batch, clearArray: true);
+                lock (_gate)
+                {
+                    _pumpScheduled = 0;
+                    if (!_queue.IsEmpty) SchedulePump();
+                }
             }
         }
     }
@@ -321,6 +392,7 @@ namespace ShrinkEventBus
         }
 
         public bool IsOnSchedulerThread => false;
+        public bool SupportsDeferred => false;
 
         public bool TryPost(Action action)
         {
@@ -337,6 +409,8 @@ namespace ShrinkEventBus
             return true;
         }
 
+        public ShrinkDeferredPostStatus TryPostDeferred(Action action) => ShrinkDeferredPostStatus.Unsupported;
+
         public async UniTask PostAsync(Func<UniTask> action, CancellationToken cancellationToken)
         {
             if (Volatile.Read(ref _disposed) != 0)
@@ -417,6 +491,7 @@ namespace ShrinkEventBus
         }
 
         public bool IsOnSchedulerThread => Thread.CurrentThread.ManagedThreadId == Volatile.Read(ref _threadId);
+        public bool SupportsDeferred => false;
 
         public bool TryPost(Action action)
         {
@@ -439,6 +514,8 @@ namespace ShrinkEventBus
             return true;
         }
 
+        public ShrinkDeferredPostStatus TryPostDeferred(Action action) => ShrinkDeferredPostStatus.Unsupported;
+
         public async UniTask PostAsync(Func<UniTask> action, CancellationToken cancellationToken)
         {
             if (Volatile.Read(ref _disposed) != 0)
diff --git a/Runtime/ShrinkEventBus.Runtime.asmdef b/Runtime/ShrinkEventBus.Runtime.asmdef
index 513bd1d..d6c2660 100644
--- a/Runtime/ShrinkEventBus.Runtime.asmdef
+++ b/Runtime/ShrinkEventBus.Runtime.asmdef
@@ -2,7 +2,8 @@
   "name": "ShrinkEventBus.Runtime",
   "rootNamespace": "ShrinkEventBus",
   "references": [
-    "UniTask"
+    "UniTask",
+    "ShrinkRuntime.Abstractions"
   ],
   "includePlatforms": [],
   "excludePlatforms": [],
diff --git a/Runtime/ShrinkEventBusInstance.cs b/Runtime/ShrinkEventBusInstance.cs
index 5465f2a..a028972 100644
--- a/Runtime/ShrinkEventBusInstance.cs
+++ b/Runtime/ShrinkEventBusInstance.cs
@@ -87,6 +87,30 @@ namespace ShrinkEventBus
             return PostScheduled(in eventData);
         }
 
+        internal ShrinkPostResult PostDeferred<TEvent>(in TEvent eventData) where TEvent : IShrinkEvent
+        {
+            if (!typeof(TEvent).IsValueType && eventData is null)
+                throw new ArgumentNullException(nameof(eventData));
+            if (Volatile.Read(ref _disposed) != 0)
+                return TraceWithoutDispatch(in eventData,
+                    ShrinkPostResult.Rejected(ShrinkPostFailure.BusStopped), false);
+            if (Options.Scheduler != ShrinkBusSchedulerKind.MainThread || !_scheduler.SupportsDeferred)
+                return TraceWithoutDispatch(in eventData,
+                    ShrinkPostResult.Rejected(ShrinkPostFailure.DeferredUnsupported), false);
+
+            var queuedEvent = eventData;
+            var status = _scheduler.TryPostDeferred(() => Dispatch(in queuedEvent));
+            if (status == ShrinkDeferredPostStatus.Accepted) return new ShrinkPostResult(true, false, false);
+            var failure = status switch
+            {
+                ShrinkDeferredPostStatus.Unsupported => ShrinkPostFailure.DeferredUnsupported,
+                ShrinkDeferredPostStatus.Stopped => ShrinkPostFailure.BusStopped,
+                ShrinkDeferredPostStatus.SchedulerRejected => ShrinkPostFailure.SchedulerRejected,
+                _ => ShrinkPostFailure.QueueFull
+            };
+            return TraceWithoutDispatch(in eventData, ShrinkPostResult.Rejected(failure), false);
+        }
+
         private ShrinkPostResult PostScheduled<TEvent>(in TEvent eventData) where TEvent : IShrinkEvent
         {
             var queuedEvent = eventData;
@@ -207,7 +231,7 @@ namespace ShrinkEventBus
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         protected ShrinkPostResult Dispatch<TEvent>(in TEvent eventData) where TEvent : IShrinkEvent
         {
-            if (_postObserver != null && EventBus.HasDetailedPostedObservers)
+            if (EventBus.HasDetailedPostedObservers)
                 return DispatchObserved(in eventData);
 
             var channel = ShrinkEventChannelSlots<TEvent>.Get(_busSlot);
@@ -222,7 +246,7 @@ namespace ShrinkEventBus
         protected async UniTask<ShrinkPostResult> DispatchAsync<TEvent>(TEvent eventData,
             CancellationToken cancellationToken) where TEvent : IShrinkEvent
         {
-            if (_postObserver != null && EventBus.HasDetailedPostedObservers)
+            if (EventBus.HasDetailedPostedObservers)
                 return await DispatchAsyncObserved(eventData, cancellationToken);
 
             var channel = ShrinkEventChannelSlots<TEvent>.Get(_busSlot);
@@ -258,8 +282,8 @@ namespace ShrinkEventBus
             }
 
             var elapsedTicks = Stopwatch.GetTimestamp() - startedAt;
-            if (EventBus.HasPostedObservers)
-                _postObserver!(eventData, typeof(TEvent), Key);
+            if (_postObserver != null && EventBus.HasPostedObservers)
+                _postObserver(eventData, typeof(TEvent), Key);
             EventBus.NotifyDetailedPosted(new ShrinkEventTrace(DateTime.UtcNow, typeof(TEvent), Key,
                 Options, threadId, elapsedTicks, result, false));
             return result;
@@ -269,7 +293,7 @@ namespace ShrinkEventBus
         protected ShrinkPostResult TraceWithoutDispatch<TEvent>(in TEvent eventData,
             ShrinkPostResult result, bool isAsync) where TEvent : IShrinkEvent
         {
-            if (_postObserver != null && EventBus.HasDetailedPostedObservers)
+            if (EventBus.HasDetailedPostedObservers)
             {
                 EventBus.NotifyDetailedPosted(new ShrinkEventTrace(DateTime.UtcNow, typeof(TEvent), Key,
                     Options, Thread.CurrentThread.ManagedThreadId, 0L, result, isAsync));
@@ -309,8 +333,8 @@ namespace ShrinkEventBus
             }
 
             var elapsedTicks = Stopwatch.GetTimestamp() - startedAt;
-            if (EventBus.HasPostedObservers)
-                _postObserver!(eventData, typeof(TEvent), Key);
+            if (_postObserver != null && EventBus.HasPostedObservers)
+                _postObserver(eventData, typeof(TEvent), Key);
             EventBus.NotifyDetailedPosted(new ShrinkEventTrace(DateTime.UtcNow, typeof(TEvent), Key,
                 Options, threadId, elapsedTicks, result, true));
             return result;
diff --git a/Runtime/ShrinkEventBusRuntime.cs b/Runtime/ShrinkEventBusRuntime.cs
index 756c0c6..464b511 100644
--- a/Runtime/ShrinkEventBusRuntime.cs
+++ b/Runtime/ShrinkEventBusRuntime.cs
@@ -37,7 +37,8 @@ namespace ShrinkEventBus
     }
 
 #if UNITY_5_3_OR_NEWER
-    internal sealed class ShrinkUnityMainThreadDispatcher : MainThreadDispatcherContract
+    internal sealed class ShrinkUnityMainThreadDispatcher : MainThreadDispatcherContract,
+        ShrinkSDK.Runtime.IShrinkDeferredMainThreadDispatcher
     {
         public bool IsMainThread => Cysharp.Threading.Tasks.PlayerLoopHelper.IsMainThread;
 
@@ -50,9 +51,20 @@ namespace ShrinkEventBus
                 action);
             return true;
         }
+
+        public bool TryPostDeferred(Action action)
+        {
+            if (action == null)
+                throw new ArgumentNullException(nameof(action));
+            Cysharp.Threading.Tasks.PlayerLoopHelper.AddContinuation(
+                Cysharp.Threading.Tasks.PlayerLoopTiming.Update,
+                action);
+            return true;
+        }
     }
 #else
-    internal sealed class ShrinkSynchronizationContextDispatcher : MainThreadDispatcherContract
+    internal sealed class ShrinkSynchronizationContextDispatcher : MainThreadDispatcherContract,
+        ShrinkSDK.Runtime.IShrinkDeferredMainThreadDispatcher
     {
         private readonly SynchronizationContext? _context;
         private readonly int _threadId;
@@ -79,6 +91,16 @@ namespace ShrinkEventBus
             _context.Post(static state => ((Action)state!).Invoke(), action);
             return true;
         }
+
+        public bool TryPostDeferred(Action action)
+        {
+            if (action == null)
+                throw new ArgumentNullException(nameof(action));
+            if (_context == null)
+                return false;
+            _context.Post(static state => ((Action)state!).Invoke(), action);
+            return true;
+        }
     }
 #endif
 }
diff --git a/Runtime/ShrinkEventContracts.cs b/Runtime/ShrinkEventContracts.cs
index 0fe5cab..0a3dd0b 100644
--- a/Runtime/ShrinkEventContracts.cs
+++ b/Runtime/ShrinkEventContracts.cs
@@ -61,7 +61,9 @@ namespace ShrinkEventBus
         QueueFull = 2,
         Canceled = 3,
         HandlerException = 4,
-        InvalidEvent = 5
+        InvalidEvent = 5,
+        DeferredUnsupported = 6,
+        SchedulerRejected = 7
     }
 
     public readonly struct ShrinkPostResult
diff --git a/Runtime/ShrinkEventDiagnostic.cs b/Runtime/ShrinkEventDiagnostic.cs
new file mode 100644
index 0000000..0ddab20
--- /dev/null
+++ b/Runtime/ShrinkEventDiagnostic.cs
@@ -0,0 +1,37 @@
+#nullable enable
+
+using System;
+using System.Diagnostics;
+
+namespace ShrinkEventBus
+{
+    public readonly struct ShrinkEventDiagnostic
+    {
+        internal ShrinkEventDiagnostic(DateTime timestampUtc, Type eventType, ShrinkBusKey busKey,
+            ShrinkBusSchedulerKind scheduler, ShrinkDispatchMode dispatchMode, int threadId,
+            long elapsedTimestampTicks, ShrinkPostResult result, bool isAsync)
+        {
+            TimestampUtc = timestampUtc;
+            EventType = eventType;
+            BusKey = busKey;
+            Scheduler = scheduler;
+            DispatchMode = dispatchMode;
+            ThreadId = threadId;
+            ElapsedTimestampTicks = elapsedTimestampTicks;
+            Result = result;
+            IsAsync = isAsync;
+        }
+
+        public DateTime TimestampUtc { get; }
+        public Type EventType { get; }
+        public ShrinkBusKey BusKey { get; }
+        public ShrinkBusSchedulerKind Scheduler { get; }
+        public ShrinkDispatchMode DispatchMode { get; }
+        public int ThreadId { get; }
+        public long ElapsedTimestampTicks { get; }
+        public double ElapsedMilliseconds => ElapsedTimestampTicks * 1000d / Stopwatch.Frequency;
+        public TimeSpan Elapsed => TimeSpan.FromSeconds(ElapsedTimestampTicks / (double)Stopwatch.Frequency);
+        public ShrinkPostResult Result { get; }
+        public bool IsAsync { get; }
+    }
+}
diff --git a/Runtime/ShrinkEventDiagnostic.cs.meta b/Runtime/ShrinkEventDiagnostic.cs.meta
new file mode 100644
index 0000000..ee5ff09
--- /dev/null
+++ b/Runtime/ShrinkEventDiagnostic.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 0dd120bc74194af29d7cbd1f8c80c141
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData:
+  assetBundleName:
+  assetBundleVariant:
diff --git a/Tests/ShrinkEventBus.Tests.asmdef b/Tests/ShrinkEventBus.Tests.asmdef
index 69004b2..c670588 100644
--- a/Tests/ShrinkEventBus.Tests.asmdef
+++ b/Tests/ShrinkEventBus.Tests.asmdef
@@ -3,6 +3,7 @@
     "rootNamespace": "ShrinkEventBus.Tests",
     "references": [
         "ShrinkEventBus.Runtime",
+        "ShrinkRuntime.Abstractions",
         "UniTask",
         "UnityEngine.TestRunner",
         "UnityEditor.TestRunner"
diff --git a/Tests/ShrinkEventBusDeferredDiagnosticsTests.cs b/Tests/ShrinkEventBusDeferredDiagnosticsTests.cs
new file mode 100644
index 0000000..bac92a3
--- /dev/null
+++ b/Tests/ShrinkEventBusDeferredDiagnosticsTests.cs
@@ -0,0 +1,251 @@
+using System;
+using System.Collections.Generic;
+using NUnit.Framework;
+using UnityEngine;
+using UnityEngine.TestTools;
+
+namespace ShrinkEventBus.Tests
+{
+    [TestFixture]
+    public class ShrinkEventBusDeferredDiagnosticsTests
+    {
+        private IShrinkEventBusMainThreadDispatcher _originalDispatcher;
+
+        [SetUp]
+        public void SetUp()
+        {
+            _originalDispatcher = ShrinkEventBusRuntime.MainThreadDispatcher;
+        }
+
+        [TearDown]
+        public void TearDown()
+        {
+            ShrinkEventBusRuntime.ConfigureMainThreadDispatcher(_originalDispatcher);
+        }
+
+        [Test]
+        public void ObserveDiagnostics_ReportsMetadataAndUnsubscribes()
+        {
+            var diagnostics = new List<ShrinkEventDiagnostic>();
+            using var host = new ShrinkEventBusHost();
+            var key = new ShrinkBusKey("diagnostics", Guid.NewGuid().ToString("N"));
+            var bus = host.CreateBus(key, ShrinkBusOptions.Inline());
+
+            var subscription = EventBus.ObserveDiagnostics(diagnostics.Add);
+            bus.Post(new DeferredEvent(1));
+            subscription.Dispose();
+            bus.Post(new DeferredEvent(2));
+
+            Assert.AreEqual(1, diagnostics.Count);
+            Assert.AreEqual(typeof(DeferredEvent), diagnostics[0].EventType);
+            Assert.AreEqual(key, diagnostics[0].BusKey);
+            Assert.IsTrue(diagnostics[0].Result.Accepted);
+            Assert.IsFalse(diagnostics[0].IsAsync);
+            Assert.GreaterOrEqual(diagnostics[0].ElapsedTimestampTicks, 0L);
+        }
+
+        [Test]
+        public void ObserveDiagnostics_ThrowingObserverDoesNotBlockBusinessOrOtherObservers()
+        {
+            var calls = 0;
+            var secondObserverCalls = 0;
+            using var host = new ShrinkEventBusHost();
+            var key = new ShrinkBusKey("diagnostics", Guid.NewGuid().ToString("N"));
+            var bus = host.CreateBus(key, ShrinkBusOptions.Inline());
+            using var binding = ShrinkGeneratedBinding.Subscribe<DeferredEvent>(host, key, string.Empty,
+                this, _ => calls++, ShrinkEventPriority.Normal, 0, false);
+            using var first = EventBus.ObserveDiagnostics(_ =>
+                throw new InvalidOperationException("observer failure"));
+            using var second = EventBus.ObserveDiagnostics(_ => secondObserverCalls++);
+
+            var previous = LogAssert.ignoreFailingMessages;
+            LogAssert.ignoreFailingMessages = true;
+            try
+            {
+                Assert.DoesNotThrow(() => bus.Post(new DeferredEvent(3)));
+            }
+            finally
+            {
+                LogAssert.ignoreFailingMessages = previous;
+            }
+
+            Assert.AreEqual(1, calls);
+            Assert.AreEqual(1, secondObserverCalls);
+        }
+
+        [Test]
+        public void PostDeferred_DoesNotDispatchBeforePump()
+        {
+            var dispatcher = new ManualDispatcher();
+            ShrinkEventBusRuntime.ConfigureMainThreadDispatcher(dispatcher);
+            using var host = new ShrinkEventBusHost();
+            var key = new ShrinkBusKey("deferred", Guid.NewGuid().ToString("N"));
+            var bus = host.CreateBus(key, new ShrinkBusOptions
+            {
+                Scheduler = ShrinkBusSchedulerKind.MainThread,
+                QueueCapacity = 8
+            });
+            var calls = 0;
+            using var binding = ShrinkGeneratedBinding.Subscribe<DeferredEvent>(host, key, string.Empty,
+                this, _ => calls++, ShrinkEventPriority.Normal, 0, false);
+
+            var result = EventBus.PostDeferred(bus, new DeferredEvent(4));
+
+            Assert.IsTrue(result.Accepted);
+            Assert.IsFalse(result.Handled);
+            Assert.AreEqual(0, calls);
+            Assert.AreEqual(1, dispatcher.Count);
+
+            dispatcher.PumpAll();
+            Assert.AreEqual(1, calls);
+        }
+
+        [Test]
+        public void PostDeferred_ReentrantPostWaitsForNextPump()
+        {
+            var dispatcher = new ManualDispatcher();
+            ShrinkEventBusRuntime.ConfigureMainThreadDispatcher(dispatcher);
+            using var host = new ShrinkEventBusHost();
+            var key = new ShrinkBusKey("deferred", Guid.NewGuid().ToString("N"));
+            var bus = host.CreateBus(key, new ShrinkBusOptions
+            {
+                Scheduler = ShrinkBusSchedulerKind.MainThread,
+                QueueCapacity = 8
+            });
+            var calls = 0;
+            using var binding = ShrinkGeneratedBinding.Subscribe<DeferredEvent>(host, key, string.Empty,
+                this, _ =>
+                {
+                    calls++;
+                    if (calls == 1)
+                        EventBus.PostDeferred(bus, new DeferredEvent(5));
+                }, ShrinkEventPriority.Normal, 0, false);
+
+            EventBus.PostDeferred(bus, new DeferredEvent(4));
+            dispatcher.PumpAll();
+            Assert.AreEqual(1, calls);
+            Assert.AreEqual(1, dispatcher.Count);
+
+            dispatcher.PumpAll();
+            Assert.AreEqual(2, calls);
+        }
+
+        [Test]
+        public void PostDeferred_DropOldestKeepsNewest()
+        {
+            var dispatcher = new ManualDispatcher();
+            ShrinkEventBusRuntime.ConfigureMainThreadDispatcher(dispatcher);
+            using var host = new ShrinkEventBusHost();
+            var key = new ShrinkBusKey("deferred", Guid.NewGuid().ToString("N"));
+            var bus = host.CreateBus(key, new ShrinkBusOptions
+            {
+                Scheduler = ShrinkBusSchedulerKind.MainThread,
+                QueueCapacity = 1,
+                OverflowPolicy = ShrinkQueueOverflowPolicy.DropOldest
+            });
+            var values = new List<int>();
+            using var binding = ShrinkGeneratedBinding.Subscribe<DeferredEvent>(host, key, string.Empty,
+                this, evt => values.Add(evt.Value), ShrinkEventPriority.Normal, 0, false);
+
+            EventBus.PostDeferred(bus, new DeferredEvent(1));
+            EventBus.PostDeferred(bus, new DeferredEvent(2));
+            dispatcher.PumpAll();
+
+            CollectionAssert.AreEqual(new[] { 2 }, values);
+        }
+
+        [Test]
+        public void PostDeferred_InlineBusFailsWithoutDispatch()
+        {
+            using var host = new ShrinkEventBusHost();
+            var key = new ShrinkBusKey("deferred", Guid.NewGuid().ToString("N"));
+            var bus = host.CreateBus(key, ShrinkBusOptions.Inline());
+            var calls = 0;
+            using var binding = ShrinkGeneratedBinding.Subscribe<DeferredEvent>(host, key, string.Empty,
+                this, _ => calls++, ShrinkEventPriority.Normal, 0, false);
+
+            var result = EventBus.PostDeferred(bus, new DeferredEvent(6));
+
+            Assert.AreEqual(ShrinkPostFailure.DeferredUnsupported, result.Failure);
+            Assert.AreEqual(0, calls);
+        }
+
+        [Test]
+        public void PostDeferred_WithoutDeferredDispatcherFailsWithoutDispatch()
+        {
+            ShrinkEventBusRuntime.ConfigureMainThreadDispatcher(new NonDeferredDispatcher());
+            using var host = new ShrinkEventBusHost();
+            var key = new ShrinkBusKey("deferred", Guid.NewGuid().ToString("N"));
+            var bus = host.CreateBus(key, new ShrinkBusOptions
+            {
+                Scheduler = ShrinkBusSchedulerKind.MainThread
+            });
+            var calls = 0;
+            using var binding = ShrinkGeneratedBinding.Subscribe<DeferredEvent>(host, key, string.Empty,
+                this, _ => calls++, ShrinkEventPriority.Normal, 0, false);
+
+            var result = EventBus.PostDeferred(bus, new DeferredEvent(7));
+
+            Assert.AreEqual(ShrinkPostFailure.DeferredUnsupported, result.Failure);
+            Assert.AreEqual(0, calls);
+        }
+
+        [Test]
+        public void PostDeferred_DisposedBusRejects()
+        {
+            var dispatcher = new ManualDispatcher();
+            ShrinkEventBusRuntime.ConfigureMainThreadDispatcher(dispatcher);
+            using var host = new ShrinkEventBusHost();
+            var key = new ShrinkBusKey("deferred", Guid.NewGuid().ToString("N"));
+            var bus = host.CreateBus(key, new ShrinkBusOptions
+            {
+                Scheduler = ShrinkBusSchedulerKind.MainThread
+            });
+            bus.Dispose();
+
+            var result = EventBus.PostDeferred(bus, new DeferredEvent(8));
+
+            Assert.AreEqual(ShrinkPostFailure.BusStopped, result.Failure);
+        }
+
+        private readonly struct DeferredEvent : IShrinkEvent
+        {
+            public DeferredEvent(int value) => Value = value;
+            public int Value { get; }
+        }
+
+        private sealed class ManualDispatcher : IShrinkEventBusMainThreadDispatcher,
+            ShrinkSDK.Runtime.IShrinkDeferredMainThreadDispatcher
+        {
+            private readonly Queue<Action> _queue = new();
+
+            public bool IsMainThread => true;
+            public int Count => _queue.Count;
+
+            public bool TryPost(Action action)
+            {
+                _queue.Enqueue(action);
+                return true;
+            }
+
+            public bool TryPostDeferred(Action action)
+            {
+                _queue.Enqueue(action);
+                return true;
+            }
+
+            public void PumpAll()
+            {
+                var count = _queue.Count;
+                for (var i = 0; i < count; i++)
+                    _queue.Dequeue()();
+            }
+        }
+
+        private sealed class NonDeferredDispatcher : IShrinkEventBusMainThreadDispatcher
+        {
+            public bool IsMainThread => true;
+            public bool TryPost(Action action) => true;
+        }
+    }
+}
diff --git a/Tests/ShrinkEventBusDeferredDiagnosticsTests.cs.meta b/Tests/ShrinkEventBusDeferredDiagnosticsTests.cs.meta
new file mode 100644
index 0000000..3039e5f
--- /dev/null
+++ b/Tests/ShrinkEventBusDeferredDiagnosticsTests.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 070c5e5975c64a39badcb0ebb04c2902
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData:
+  assetBundleName:
+  assetBundleVariant:
diff --git a/package.json b/package.json
index d98d4e4..28fc84c 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "com.cneicy.shrink-eventbus",
-  "version": "2.2.3",
+  "version": "2.3.1",
   "displayName": "ShrinkEventBus",
   "description": "多 Bus、特性强类型注册、UniTask 调度与低分配发布的 Unity 事件总线。",
   "unity": "2022.3",
@@ -9,7 +9,8 @@
   "licensesUrl": "https://github.com/cneicy/ShrinkEventBus/blob/main/LICENSE",
   "dependencies": {
     "com.cysharp.unitask": "2.5.10",
-    "com.unity.nuget.mono-cecil": "1.11.4"
+    "com.unity.nuget.mono-cecil": "1.11.4",
+    "com.cneicy.shrink-runtime-abstractions": "0.2.0"
   },
   "keywords": [
     "eventbus",