From b7a9e6ccfacf2dd97f2ec31202c5191cb875b917 Mon Sep 17 00:00:00 2001
From: cliu31 <chen.liu1@rockwellautomation.com>
Date: Mon, 13 Jul 2026 08:32:57 +0800
Subject: [PATCH] fix(#436): resolve race condition in EmitAsync

---
 src/SocketIOClient/SocketIO.cs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/SocketIOClient/SocketIO.cs b/src/SocketIOClient/SocketIO.cs
index e7182886..d8cb82ff 100644
--- a/src/SocketIOClient/SocketIO.cs
+++ b/src/SocketIOClient/SocketIO.cs
@@ -283,13 +283,15 @@ public async Task EmitAsync(
         CancellationToken cancellationToken)
     {
         CheckStatusAndData(data);
+        int packetId;
         lock (_ackHandlerLock)
         {
             _packetId++;
-            _ackHandlers.Add(_packetId, ack);
+            packetId = _packetId;
+            _ackHandlers.Add(packetId, ack);
         }
         var sessionData = MergeEventData(eventName, data);
-        await _session!.SendAsync(sessionData, _packetId, cancellationToken).ConfigureAwait(false);
+        await _session!.SendAsync(sessionData, packetId, cancellationToken).ConfigureAwait(false);
     }
 
     public async Task EmitAsync(string eventName, IEnumerable<object> data, Func<IDataMessage, Task> ack)