write and flush methods are provided (#346)

src/main/java/com/alipay/remoting/RemotingContext.java

@@ -105,13 +105,31 @@ public RemotingContext(ChannelHandlerContext ctx, InvokeContext invokeContext,
     /**
      * Wrap the writeAndFlush method.
      * 
-     * @param msg
-     * @return
+     * @param msg as msg
+     * @return channel future
      */
     public ChannelFuture writeAndFlush(RemotingCommand msg) {
         return this.channelContext.writeAndFlush(msg);
     }
 
+    /**
+     * Wrap the write method.
+     *
+     * @param msg as msg
+     * @return channel future
+     */
+    public ChannelFuture write(RemotingCommand msg) {
+        return this.channelContext.write(msg);
+    }
+
+    /**
+     * Wrap the write method.
+     *
+     */
+    public void flush() {
+        this.channelContext.flush();
+    }
+
     /**
      * whether this request already timeout
      *