fix: handle possible UnobservedTaskException

src/FeatBit.ServerSdk/DataSynchronizer/WebSocketDataSynchronizer.cs

@@ -8,6 +8,7 @@
 using FeatBit.Sdk.Server.Options;
 using FeatBit.Sdk.Server.Store;
 using FeatBit.Sdk.Server.Transport;
+using FeatBit.Sdk.Server.Utils;
 using Microsoft.Extensions.Logging;
 
 namespace FeatBit.Sdk.Server.DataSynchronizer
@@ -66,7 +67,7 @@ private static FbWebSocket DefaultFbWebSocketFactory(FbOptions options)
 
         public Task<bool> StartAsync()
         {
-            Task.Run(() => _webSocket.ConnectAsync());
+            _webSocket.ConnectAsync().Forget();
 
             return _initTcs.Task;
         }

src/FeatBit.ServerSdk/Transport/FbWebSocket.cs

@@ -304,7 +304,15 @@ private void CompleteClose(Exception exception = null, string message = "")
 
         private async Task KeepAliveAsync(CancellationToken ct = default)
         {
-            await SendAsync(PingMessage, ct);
+            try
+            {
+                await SendAsync(PingMessage, ct);
+            }
+            catch (InvalidOperationException)
+            {
+                // the pipe write will throw InvalidOperationException if the connection is closed
+                // catch and ignore it to avoid UnobservedTaskException
+            }
 
             Log.InvokingEventHandler(_logger, nameof(OnKeepAlive));
             _ = OnKeepAlive?.Invoke();

src/FeatBit.ServerSdk/Utils/TaskExtensions.cs

@@ -0,0 +1,37 @@
+using System.Threading.Tasks;
+
+namespace FeatBit.Sdk.Server.Utils;
+
+public static class TaskExtensions
+{
+    /// <summary>
+    /// Observes the task to avoid the UnobservedTaskException event to be raised.
+    /// </summary>
+    public static void Forget(this Task task)
+    {
+        if (!task.IsCompleted || task.IsFaulted)
+        {
+            _ = ForgetAwaited(task);
+        }
+
+        return;
+
+        static async Task ForgetAwaited(Task task)
+        {
+#if NET8_0_OR_GREATER
+            await task.ConfigureAwait(ConfigureAwaitOptions.SuppressThrowing);
+#else
+
+            try
+            {
+                // No need to resume on the original SynchronizationContext, so use ConfigureAwait(false)
+                await task.ConfigureAwait(false);
+            }
+            catch
+            {
+                // Nothing to do here
+            }
+#endif
+        }
+    }
+}