Add byte rate metrics

For now it's only added to AsyncCommand.

AerospikeClient/Async/AsyncConnectionArgs.cs

@@ -131,6 +131,8 @@ private void SendEvent(SocketAsyncEventArgs args)
 					return;
 				}
 
+				node.IncrBytesWritten(sent);
+
 				if (sent < args.Count)
 				{
 					args.SetBuffer(args.Offset + sent, args.Count - sent);
@@ -172,6 +174,8 @@ private void ReceiveEvent(SocketAsyncEventArgs args)
 					return;
 				}
 
+				node.IncrBytesRead(received);
+
 				if (received < args.Count)
 				{
 					args.SetBuffer(args.Offset + received, args.Count - received);

AerospikeClient/Async/AsyncNode.cs

@@ -26,6 +26,8 @@ public sealed class AsyncNode : Node
 		private readonly new AsyncCluster cluster;
 		private int asyncConnsOpened;
 		private int asyncConnsClosed;
+		private int bytesRead;
+		private int bytesWritten;
 
 		/// <summary>
 		/// Initialize server node with connection parameters.
@@ -196,6 +198,16 @@ internal void IncrAsyncConnClosed()
 			Interlocked.Increment(ref asyncConnsClosed);
 		}
 
+		public void IncrBytesRead(int bytesRead)
+		{
+			Interlocked.Increment(ref this.bytesRead);
+		}
+
+		public void IncrBytesWritten(int bytesWritten)
+		{
+			Interlocked.Increment(ref this.bytesWritten);
+		}
+
 		public ConnectionStats GetAsyncConnectionStats()
 		{
 			int inPool = asyncConnQueue.Count;
@@ -206,7 +218,7 @@ public ConnectionStats GetAsyncConnectionStats()
 			{
 				inUse = 0;
 			}
-			return new ConnectionStats(inPool, inUse, asyncConnsOpened, asyncConnsClosed);
+			return new ConnectionStats(inPool, inUse, asyncConnsOpened, asyncConnsClosed, bytesRead, bytesWritten);
 		}
 	}
 }

AerospikeClient/Cluster/ClusterStats.cs

@@ -122,7 +122,7 @@ public NodeStats(Node node)
 			}
 			else
 			{
-				this.asyncStats = new ConnectionStats(0, 0, 0, 0);
+				this.asyncStats = new ConnectionStats(0, 0, 0, 0, 0, 0);
 			}
 		}
 
@@ -159,24 +159,36 @@ public sealed class ConnectionStats
 		/// Total number of node connections closed since node creation.
 		/// </summary>
 		public readonly int closed;
-
+
+		/// <summary>
+		/// Total number of bytes read from that connection.
+		/// </summary>
+		public readonly int bytesRead;
+
+		/// <summary>
+		/// Total number of bytes written to that connection.
+		/// </summary>
+		public readonly int bytesWritten;
+
 		/// <summary>
 		/// Connection statistics constructor.
 		/// </summary>
-		public ConnectionStats(int inPool, int inUse, int opened, int closed)
+		public ConnectionStats(int inPool, int inUse, int opened, int closed, int bytesRead, int bytesWritten)
 		{
 			this.inPool = inPool;
 			this.inUse = inUse;
 			this.opened = opened;
 			this.closed = closed;
+			this.bytesRead = bytesRead;
+			this.bytesWritten = bytesWritten;
 		}
 
 		/// <summary>
 		/// Convert statistics to string.
 		/// </summary>
 		public override string ToString()
 		{
-			return "" + inUse + ',' + inPool + ',' + opened + ',' + closed;
+			return "" + inUse + ',' + inPool + ',' + opened + ',' + closed + ',' + bytesRead + ',' + bytesWritten;
 		}
 	}
 }

AerospikeClient/Cluster/Node.cs

@@ -831,7 +831,7 @@ public ConnectionStats GetConnectionStats()
 				}
 				inUse += tmp;
 			}
-			return new ConnectionStats(inPool, inUse, connsOpened, connsClosed);
+			return new ConnectionStats(inPool, inUse, connsOpened, connsClosed, -1, -1);
 		}
 
 		public void IncrErrorCount()