Assistance with custom ICoapEndpoint

[malachib]

Hi, first of all I want to say thank you for the library. I'm a bit of a CoAP nut (see https://github.com/malachi-iot/mc-coap ) and we are utilizing your lib to talk over a fully custom network transport.

We are encountering a mysterious problem where MID (and some other portion, I'm sure) maybe don't match up on responses so we end up doing a ton of retries. I am rather confident this is due to some failing of our own ICoapEndpoint, but I was wondering if you could share any wisdom or thoughts?

Inspection of MID's themselves appear to all be proper

Full disclosure: I write the ICoapEndpoint before realizing that it's an endpoint and transport at once, so all incoming traffic is funneling through one singleton ICoapEndpoint and one singleton CoapClient. However, all these tests are against only one target, so hopefully in the short term that's not too bad. I plan to remedy that scenario in the next round of coding