submodule对gitea不管用，所以直接拉了一份拉格兰

Lagrange.Core/Lagrange.OneBot/Message/SegmentSubscriberAttribute.cs

@@ -0,0 +1,11 @@
+namespace Lagrange.OneBot.Message;
+
+[AttributeUsage(AttributeTargets.Class)]
+public class SegmentSubscriberAttribute(Type entity, string type, string? sendType = null) : Attribute
+{
+    public Type Entity { get; } = entity;
+
+    public string Type { get; } = type;
+
+    public string SendType { get; } = sendType ?? type;
+}