MVP: Client

[ShadowJonathan]

The following behaviour must be present for the first MVP implementation of lb:

• Wholesale serialisation of requests from ruma types (integer translation not required for requests at this stage)
• CBOR Integer key translation to corresponding string-key counterparts
• Wholesale deserialisation of responses onto ruma types (with integer key translation)
• DTLS + CoAP connection establishment
• CoAP sync OBSERVE exposure (futures channel? Simple try_next()?)

[ShadowJonathan]

There’s a bunch of options to start with, I think;

• sync single-thread blocking client
• sync single-thread blocking client, with a separate thread looping for observe messages
• “Async” multi-thread blocking client
• full rust-futures async client

out of those all, I think the first (request a single COAP request on a single connection at a time, and block on it) would be the easiest to start off with