private void assertCommand(final String cmd, final String expect) {
                    if (!expect.equals(cmd)) {
                        throw new MetaCodecException("Expect " + expect + ",but was " + cmd);
                    }
                }
result code length opaque\r\n message

@param buff
@param sa
@return
metamorphosis-commons/src/main/java/com/taobao/metamorphosis/network/MetamorphosisWireFormatType.java