public static final byte FLAG_JSON_BODY = 16;
public static final byte HB_PACKET_BYTE = -33;
public static final byte[] HB_PACKET_BYTES = new byte[]{HB_PACKET_BYTE};
public static final Packet HB_PACKET = new Packet(Command.HEARTBEAT);
public byte cmd; //命令
<BUG>public short cc; //校验码 暂时没有用到
</BUG>
public byte flags; //特性，如是否加密，是否压缩等
public int sessionId; // 会话id。客户端生成。
<BUG>public byte lrc; // 校验，纵向冗余校验。只校验head

public byte[] body;
</BUG>
public Packet(byte cmd) {

public static final byte FLAG_JSON_BODY = 16;
public static final byte HB_PACKET_BYTE = -33;
public static final byte[] HB_PACKET_BYTES = new byte[]{HB_PACKET_BYTE};
public static final Packet HB_PACKET = new Packet(Command.HEARTBEAT);
public byte cmd; //命令
transient public short cc; //校验码 暂时没有用到
public byte flags; //特性，如是否加密，是否压缩等
public int sessionId; // 会话id。客户端生成。
transient public byte lrc; // 校验，纵向冗余校验。只校验head
transient public byte[] body;
public Packet(byte cmd) {
