don’t await if there are no callbacks

Author: denrase

packages/dart/lib/src/protocol/sentry_span.dart

@@ -78,7 +78,10 @@ class SentrySpan extends ISentrySpan {
     }
 
     // Dispatch OnSpanFinish lifecycle event
-    await _hub.options.lifecycleRegistry.dispatchCallback(OnSpanFinish(this));
+    final callback = _hub.options.lifecycleRegistry.dispatchCallback(OnSpanFinish(this));
+    if (callback is Future) {
+      await callback;
+    }
 
     // The finished flag depends on the _endTimestamp
     // If we set this earlier then finished is true and then we cannot use setData etc...

packages/dart/lib/src/sdk_lifecycle_hooks.dart

@@ -34,7 +34,17 @@ class SdkLifecycleRegistry {
     callbacks?.remove(callback);
   }
 
-  FutureOr<void> dispatchCallback<T extends SdkLifecycleEvent>(T event) async {
+  FutureOr<void> dispatchCallback<T extends SdkLifecycleEvent>(T event) {
+    final callbacks = _lifecycleCallbacks[event.runtimeType];
+    if (callbacks == null || callbacks.isEmpty) {
+      // Return synchronously when there are no callbacks to avoid unnecessary async boundary
+      return null;
+    }
+    return _dispatchCallbackAsync(event, callbacks);
+  }
+
+  Future<void> _dispatchCallbackAsync<T extends SdkLifecycleEvent>(
+      T event, List<Function> callbacks) async {
     final callbacks = _lifecycleCallbacks[event.runtimeType] ?? [];
     for (final cb in callbacks) {
       try {