fix: prevent OnPerformanceTickData from sending data on null

If something causes an exception it's possible that the profiler never allocates data. in these cases, there is no point in sending data outside of MLAPI

Author: kvassall-unity

com.unity.multiplayer.mlapi/Runtime/Core/NetworkManager.cs

@@ -652,11 +652,7 @@ public void NetworkUpdate(NetworkUpdateStage updateStage)
 
         private void OnNetworkEarlyUpdate()
         {
-            PerformanceDataManager.BeginNewTick();
-            if (NetworkConfig.NetworkTransport is ITransportProfilerData profileTransport)
-            {
-                profileTransport.BeginNewTick();
-            }
+            ProfilerBeginTick();
 
             if (IsListening)
             {
@@ -760,13 +756,7 @@ private void OnNetworkPreUpdate()
                 }
             }
 
-            if (NetworkConfig.NetworkTransport is ITransportProfilerData profileTransport)
-            {
-                var transportProfilerData = profileTransport.GetTransportProfilerData();
-                PerformanceDataManager.AddTransportData(transportProfilerData);
-            }
-
-            OnPerformanceDataEvent?.Invoke(PerformanceDataManager.GetData());
+            NotifyProfilerListeners();
         }
 
         internal void UpdateNetworkTime(ulong clientId, float netTime, float receiveTime, bool warp = false)
@@ -1495,5 +1485,37 @@ internal void HandleApproval(ulong clientId, bool createPlayerObject, ulong? pla
                 NetworkConfig.NetworkTransport.DisconnectRemoteClient(clientId);
             }
         }
+
+        private void ProfilerBeginTick()
+        {
+            PerformanceDataManager.BeginNewTick();
+            if (NetworkConfig.NetworkTransport is ITransportProfilerData profileTransport)
+            {
+                profileTransport.BeginNewTick();
+            }
+        }
+
+        private void NotifyProfilerListeners()
+        {
+            var data = PerformanceDataManager.GetData();
+            var eventHandler = OnPerformanceDataEvent;
+            if (eventHandler != null)
+            {
+                if (data != null)
+                {
+                    if (NetworkConfig.NetworkTransport is ITransportProfilerData profileTransport)
+                    {
+                        var transportProfilerData = profileTransport.GetTransportProfilerData();
+                        PerformanceDataManager.AddTransportData(transportProfilerData);
+                    }
+
+                    eventHandler.Invoke(data);
+                }
+                else
+                {
+                    NetworkLog.LogWarning("No data available. Did you forget to call PerformanceDataManager.BeginNewTick() first?");
+                }
+            }
+        }
     }
 }