New create a Packet instance.

Data represents a common data packet.

Handshake represents a handshake: request(client) <====> handshake response(server).

HandshakeAck represents a handshake ack from client to server.

Heartbeat represents a heartbeat.

disconnect message from server.

ErrWrongPacketType represents a wrong packet type.

Packet represents a network packet.

Type represents the network packet's type such as: handshake and so on.