Behaviour for an outbound HTTP transport, the client-side dual of livery_adapter.

An adapter owns the wire: it takes a livery_client:request() and produces a livery_client:response() (or an error). The composable layers (timeout, retry, concurrency, circuit breaker) sit above it and do not care which transport runs underneath. The default adapter is livery_client_hackney (HTTP/1.1, HTTP/2, and HTTP/3 via hackney); write your own to front a different client.

Callbacks

• request(Request, Opts) -> {ok, Response} | {error, term()} - send one request. The adapter owns its connections and pooling.

• read(Reader, Timeout) -> {ok, Data, Reader} | {done, Reader} | {error, term()} - optional; pull the next chunk of a streamed response body. Only adapters that return a {stream, Reader} response body implement it.