public void invokeWithCallback(final Connection conn, final Object request,
                                   final InvokeCallback invokeCallback, final int timeoutMillis)
                                                                                                throws RemotingException {
        ensureStarted();
        this.rpcRemoting.invokeWithCallback(conn, request, null, invokeCallback, timeoutMillis);
    }
Callback invocation using a {@link Connection} <br>
You can specify an implementation of {@link InvokeCallback} to get the result.
<p>
Notice:<br>
  <b>DO NOT modify the request object concurrently when this method is called.</b>

@param conn connection connection
@param request request request
@param invokeCallback invokeCallback invokeCallback
@param timeoutMillis timeoutMillis  timeoutMillis
@throws RemotingException remoting exception remoting exception
src/main/java/com/alipay/remoting/rpc/RpcServer.java