doc(coapcore): Initial documentation

src/lib/coapcore/src/lib.rs

@@ -1,4 +1,16 @@
+//! A CoAP stack for embedded devices with built-in OSCORE/EDHOC support
+//! ====================================================================
+//!
+//! This crate provides an asynchronous task that serves CoAP requests on a UDP port provided by
+//! the application as an `embedded-nal` socket, and process CoAP along with its security
+//! components OSCORE and EDHOC before passing on authorized requests to the application.
+//!
+//! The crate is under heavy development: Its API is in flux, and so far it does not yet provide
+//! the CoAP server itself, but merely a middleware. (Providing the full CoAP will be a requirement
+//! for at least as long as the OSCORE component is tightly coupled to a particular implementation
+//! of [`coap-message`]).
 #![no_std]
+
 // Might warrant a standalone crate at some point
 //
 // This is pub only to make the doctests run (but the crate's pub-ness needs a major overhaul