diff --git a/Realtime/Realtime.Test/Throttle.cs b/Realtime/Realtime.Test/Throttle.cs
new file mode 100644
index 0000000..f25c651
--- /dev/null
+++ b/Realtime/Realtime.Test/Throttle.cs
@@ -0,0 +1,71 @@
+using NUnit.Framework;
+using System;
+using System.Threading.Tasks;
+using LeanCloud;
+using LeanCloud.Realtime;
+using LeanCloud.Realtime.Internal.Protocol;
+
+namespace Realtime.Test {
+    public class Throttle {
+        private LCIMClient c1;
+        private LCIMClient c2;
+
+        private LCIMConversation conversation;
+
+        [SetUp]
+        public async Task SetUp() {
+            LCLogger.LogDelegate += Utils.Print;
+            LCApplication.Initialize("ikGGdRE2YcVOemAaRbgp1xGJ-gzGzoHsz", "NUKmuRbdAhg1vrb2wexYo1jo", "https://ikggdre2.lc-cn-n1-shared.com");
+            c1 = new LCIMClient(Guid.NewGuid().ToString());
+            c2 = new LCIMClient(Guid.NewGuid().ToString());
+            await c1.Open();
+            await c2.Open();
+
+            conversation = await c1.CreateConversation(new string[] { Guid.NewGuid().ToString() });
+        }
+
+        [TearDown]
+        public async Task TearDown() {
+            await c1.Close();
+            await c2.Close();
+            LCLogger.LogDelegate -= Utils.Print;
+        }
+
+        [Test]
+        public void Equality() {
+            GenericCommand cmd1 = new GenericCommand {
+                Cmd = CommandType.Session,
+                Op = OpType.Open,
+                PeerId = "hello",
+                I = 1,
+                SessionMessage = new SessionCommand {
+                    Code = 123
+                }
+            };
+            GenericCommand cmd2 = new GenericCommand {
+                Cmd = CommandType.Session,
+                Op = OpType.Open,
+                PeerId = "hello",
+                I = 2,
+                SessionMessage = new SessionCommand {
+                    Code = 123
+                }
+            };
+            Assert.IsFalse(Equals(cmd1, cmd2));
+            cmd2.I = cmd1.I;
+            Assert.IsTrue(Equals(cmd1, cmd2));
+        }
+
+        [Test]
+        public async Task CreateSameConversation() {
+            Task t1 = conversation.RemoveMembers(new string[] { c2.Id }).ContinueWith(t => {
+                Assert.IsTrue(t.IsCompleted && !t.IsFaulted);
+            });
+            Task t2 = conversation.RemoveMembers(new string[] { c2.Id }).ContinueWith(t => {
+                Assert.IsTrue(t.IsCompleted && !t.IsFaulted);
+            });
+
+            await Task.WhenAll(t1, t2);
+        }
+    }
+}
diff --git a/Realtime/Realtime/Internal/Connection/LCConnection.cs b/Realtime/Realtime/Internal/Connection/LCConnection.cs
index 0c8de85..c4703fa 100644
--- a/Realtime/Realtime/Internal/Connection/LCConnection.cs
+++ b/Realtime/Realtime/Internal/Connection/LCConnection.cs
@@ -135,13 +135,14 @@ namespace LeanCloud.Realtime.Internal.Connection {
                     request.I = item.I;
                     return Equals(request, item);
                 });
-                if (sendingReq == null) {
-                    sendingRequests.Add(request);
-                } else {
+                if (sendingReq != null) {
                     LCLogger.Warn("duplicated request");
                     if (responses.TryGetValue(sendingReq.I, out TaskCompletionSource<GenericCommand> waitingTcs)) {
                         return await waitingTcs.Task;
                     }
+                    LCLogger.Error($"error request: {request}");
+                } else {
+                    sendingRequests.Add(request);
                 }
             }