feat: make Unity integration optional

Development~/UnityProject/Assets/ConsumerTests/ConsumerTests.cs

@@ -0,0 +1,44 @@
+using System.Collections;
+using System.Threading;
+using Cysharp.Threading.Tasks;
+using NUnit.Framework;
+using ShrinkEventBus;
+using UnityEngine.TestTools;
+
+namespace EventBusConsumer
+{
+    internal readonly struct Ping : IShrinkEvent { }
+
+    [ShrinkEventSubscriber]
+    internal sealed class Subscriber
+    {
+        public int SyncHits;
+        public int AsyncHits;
+        [ShrinkSubscribe] private void OnPing(Ping value) => SyncHits++;
+        [ShrinkSubscribe] private async UniTask OnPingAsync(Ping value, CancellationToken token)
+        {
+            await UniTask.Yield(cancellationToken: token);
+            AsyncHits++;
+        }
+    }
+
+    public sealed class ConsumerTests
+    {
+        [UnityTest]
+        public IEnumerator ConsumerAssemblyGeneratesBindingsAndDisposesThem()
+        {
+            using var host = new ShrinkEventBusHost();
+            var bus = host.CreateBus(ShrinkBusKey.Game, ShrinkBusOptions.Inline());
+            var target = new Subscriber();
+            Assert.IsInstanceOf<IShrinkGeneratedSubscriber>(target);
+            var binding = host.Attach(target, ShrinkBusKey.Game);
+            yield return bus.PostAsync(new Ping()).ToCoroutine();
+            Assert.AreEqual(1, target.SyncHits);
+            Assert.AreEqual(1, target.AsyncHits);
+            binding.Dispose();
+            yield return bus.PostAsync(new Ping()).ToCoroutine();
+            Assert.AreEqual(1, target.SyncHits);
+            Assert.AreEqual(1, target.AsyncHits);
+        }
+    }
+}