src/main/java/com/alipay/remoting/rpc/RpcClient.java
public Object invokeSync(final Connection conn, final Object request, final int timeoutMillis)
                                                                                                  throws RemotingException,
                                                                                                  InterruptedException {
        return this.rpcRemoting.invokeSync(conn, request, null, timeoutMillis);
    }
public Object invokeSync(final Connection conn, final Object request, final int timeoutMillis)
                                                                                                  throws RemotingException,
                                                                                                  InterruptedException {
        return this.rpcRemoting.invokeSync(conn, request, null, timeoutMillis);
    }
Synchronous invocation using a {@link Connection} <br>
<p>
Notice:<br>
<b>DO NOT modify the request object concurrently when this method is called.</b>

@param conn
@param request
@param timeoutMillis
@return Object
@throws RemotingException
@throws InterruptedException