WIP: Implement a Tokio Codec for SIP

[csicar]

not sure if you would want add a Tokio Codec rsip

In case you do, I'd clean this up, add more tests and an example.

Also: It seems that you don't yet use a logging system (which could be useful for clients). If you want, I'd add that in as well to replace the println macro calls

[vasilakisfil]

Hi @csicar. Implementing Tokio codec is on my TODO list :) basically you need that if you are going to use a non-UDP connection. So your code will be quite useful for me, thanks for that. Regarding logging, I have tried to avoid that and implement anything that related to logging to errors instead and let the user of rsip decide what to do with that. I haven't looked much to Tokio codec, but if logging is something that makes sense to include there, I won't hesitate to do that, after all the whole thing will be very probably under a feature flag.

At the moment and for the next 1-2 months, I am focusing on some things on dialogs/TU in the viska sip framework that uses rsip, but will come back here very soon since there I have only implemented UDP transport and TCP transport is my very next thing to do.

Leaving this open until I address it properly.

[csicar]

That sounds great. In that case I'll clean the PR up, so that it could be merged.

The codec is already testes with Twinkle.

In reads to logging: I think logging the raw sip requests could come in handy for library users. I also agree, that it would need to be behind a feature flag