code: public static Protocol getProtocol(byte code) {
          Protocol protocol = TYPE_PROTOCOL_MAP.get(code);
          if (protocol == null) {
              throw new SofaRpcRuntimeException("Extension Not Found :\"" + code + "\"!");
          }
          return protocol;
      }
docs: 按协议编号返回协议对象
  
  @param code 协议编码
  @return 协议对象