Module relay

This module implements the relaying protocol used the crate::server and crate::client.

Protocol flow:

Login:

• client connects
• -> client sends FrameType::ClientInfo

Steady state:

• server occasionally sends FrameType::KeepAlive (or FrameType::Ping)
• client responds to any FrameType::Ping with a FrameType::Pong
• clients sends FrameType::SendPacket
• server then sends FrameType::RecvPacket to recipient

Constants

• MAX_PACKET_SIZE
  The maximum size of a packet sent over relay. (This only includes the data bytes visible to magicsock, not including its on-wire framing overhead)