Fixed an issue with RelayUtpClient cleanup where its disconnect message wouldn't get through to the host.

Assets/Scripts/Game/GameManager.cs

                 m_relaySetup = null;
             }
             if (m_relayClient != null)
-            {   Component.Destroy(m_relayClient);
+            {
+                m_relayClient.Dispose();
+                Component.Destroy(m_relayClient);
                 m_relayClient = null;
             }
         }

Assets/Scripts/Relay/RelayUtpClient.cs

-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using Unity.Networking.Transport;
 using UnityEngine;
 
     /// This observes the local player and updates remote players over Relay when there are local changes, demonstrating basic data transfer over the Unity Transport (UTP).
     /// Created after the connection to Relay has been confirmed.
     /// </summary>
-    public class RelayUtpClient : MonoBehaviour // This is a MonoBehaviour merely to have access to Update.
+    public class RelayUtpClient : MonoBehaviour, IDisposable // This is a MonoBehaviour merely to have access to Update.
     {
         protected LobbyUser m_localUser;
         protected LocalLobby m_localLobby;
 
         protected bool m_hasSentInitialMessage = false;
         private const float k_heartbeatPeriod = 5;
+        private bool m_hasDisposed = false;
 
         protected enum MsgType { Ping = 0, NewPlayer, PlayerApprovalState, ReadyState, PlayerName, Emote, StartCountdown, CancelCountdown, ConfirmInGame, EndInGame, PlayerDisconnect }
 
             m_localUser.onChanged -= OnLocalChange;
             Leave();
             Locator.Get.UpdateSlow.Unsubscribe(UpdateSlow);
-            m_connections.Clear();
-            m_networkDriver.Dispose();
+            // Don't clean up the NetworkDriver here, or else our disconnect message won't get through to the host. The host will handle cleaning up the connection.
+        }
+
+        public void Dispose()
+        {
+            if (!m_hasDisposed)
+            {
+                Uninitialize();
+                m_hasDisposed = true;
+            }
+
-            Uninitialize();
+            Dispose();
         }
 
         private void OnLocalChange(LobbyUser localUser)

Assets/Scripts/Relay/RelayUtpHost.cs

         {
             base.Uninitialize();
             Locator.Get.Messenger.Unsubscribe(this);
+            m_networkDriver.Dispose();
         }
 
         protected override void OnUpdate()