private void logDebugInfo(RemotingCommand requestCommand) {
        if (logger.isDebugEnabled()) {
            logger.debug("Send request, requestId=" + requestCommand.getId());
        }
    }
Convert application request object to remoting request command.

@param request
@param conn
@param timeoutMillis
@return
@throws CodecException
src/main/java/com/alipay/remoting/rpc/RpcRemoting.java