Ensuring that RunListener/RunListenerAsync blocks until it has initialised.

Author: Chriztiaan

PowerSync/PowerSync.Common/Utils/EventStream.cs

@@ -53,16 +53,20 @@ public CancellationTokenSource RunListenerAsync(
     Func<T, Task> callback)
     {
         var cts = new CancellationTokenSource();
+        var started = new TaskCompletionSource<bool>();
 
         _ = Task.Run(async () =>
         {
+            started.SetResult(true);
             await foreach (var value in ListenAsync(cts.Token))
             {
                 await callback(value);
             }
 
         }, cts.Token);
 
+        started.Task.GetAwaiter().GetResult();
+
         return cts;
     }
 
@@ -76,15 +80,19 @@ public IAsyncEnumerable<T> ListenAsync(CancellationToken cancellationToken)
     public CancellationTokenSource RunListener(Action<T> callback)
     {
         var cts = new CancellationTokenSource();
+        var started = new TaskCompletionSource<bool>();
 
         _ = Task.Run(() =>
         {
+            started.SetResult(true);
             foreach (var value in Listen(cts.Token))
             {
                 callback(value);
             }
         }, cts.Token);
 
+        started.Task.GetAwaiter().GetResult();
+
         return cts;
     }