Required callbacks?

I have used a packet sniffer and to my shock, the packets are perfectly unprotected and are out there just waiting to be misused. Can you please add an ability to have a callback for both incoming and outgoing data for encryption purposes?

No files, tests, or entry points are named. First trace how PodSixNet handles incoming and outgoing data, then determine the callback contract and encryption responsibilities; done means both directions can be processed through callbacks without breaking normal networking.

Written by the indexing model from the issue text.