Tune BindingProxies

- Increase concurrency
- Remove unecessary assertion

CHANGES.md

@@ -90,6 +90,8 @@ To be released.
     in the same chain, since these virtually never become valid.  [[#721], [#728]]
  -  `Swarm<T>` became not to fill blocks if received block hashes are
     continuous.  [[#732]]
+ -  `Swarm<T>` became to can process more requests at once by creating TURN
+    relaying proxy concurrently.  [[TBD]]
 
 ### Bug fixes
 

Libplanet/Net/Swarm.cs

@@ -3,7 +3,6 @@
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Collections.Immutable;
-using System.Diagnostics;
 using System.IO;
 using System.Linq;
 using System.Net;
@@ -449,6 +448,9 @@ public async Task StartAsync(
                 );
                 EndPoint = new DnsEndPoint(turnEp.Address.ToString(), turnEp.Port);
 
+                // FIXME should be parameterized
+                tasks.Add(BindingProxies(_cancellationToken));
+                tasks.Add(BindingProxies(_cancellationToken));
                 tasks.Add(BindingProxies(_cancellationToken));
                 tasks.Add(RefreshAllocate(_cancellationToken));
                 tasks.Add(RefreshPermissions(_cancellationToken));
@@ -1190,7 +1192,6 @@ private async Task BindingProxies(CancellationToken cancellationToken)
                     {
                         using (var proxy = new NetworkStreamProxy(stream))
                         {
-                            Debug.Assert(_listenPort != null, nameof(_listenPort) + " != null");
                             await proxy.StartAsync(IPAddress.Loopback, _listenPort.Value);
                         }
                     }).ContinueWith(_ => stream.Dispose());