Package utp implements uTP, the micro transport protocol as used with Bittorrent. It opts for simplicity and reliability over strict adherence to the (poor) spec.

• Multiple uTP connections switched on a single PacketConn, including those initiated locally.
• Raw access to the PacketConn for non-uTP purposes, like sharing the PacketConn with a DHT implementation.

• Receive window size is used to limit out of order packets received.
• There is no MTU path discovery. The minimum size is always used.
• A fixed 64 slot selective ack window is used in both sending and receiving.
• All received non-ACK packets are ACKed in response.

Patches welcomed.