implement TcpStream.get_extra_info("original_addr")

[decathorpe]

The original packet destination address is required for implementing a "transparent mode" based on mitmproxy_wireguard. Its sockets are handled internally and not by the operating system, so it needs to expose this information in TcpStream instances.

[decathorpe]

Hum, my bad, looks like we already have this, though the property name is original_dst here and not original_addr as it is referred to in the mitmproxy source code.