public Builder clear() {
        super.clear();
        messageId_ = 0L;
        bitField0_ = (bitField0_ & ~0x00000001);
        putCommand_ = com.google.protobuf.ByteString.EMPTY;
        bitField0_ = (bitField0_ & ~0x00000002);
        return this;
      }
Protobuf type {@code com.taobao.tddl.dbproxy.protocol.AppendMessageCommand}
metamorphosis-server/src/main/java/com/taobao/metamorphosis/server/transaction/store/TransactionCommands.java