An asynchronous CoAP client with pluggable backends, intended to provide a straightforward API, allow use with tokio/async-std/smolctp/anything else, to support all the standard UDP/DTLS/TCP/TLS transports, and eventually to work with no_std.
There's also a little client utility that may be useful for working on CoAP things, installable via cargo install coap-client or by downloading pre-built images from the releases page.
This is very much a work in progress (but, hopefully a useful one!), check out the Project Status meta-issue for where we're up to.