@callback authorized?(Plug.Conn.t()) :: boolean()

Decides whether a request may proceed, before its body is read.

Optional. Implement it whenever authentication needs nothing but the request line and headers — a shared token, an API key — and the router will reject unauthorized callers with a 401 without parsing anything. Skipping it means an unauthenticated stranger can make the server read and parse a megabytes-long body before being turned away, which is free work for them and expensive for you.

Do not implement it for provider signatures computed over the raw body: those need the body, so they belong in handle_inbound/1. An adapter that omits this callback is not treated as unauthenticated — it is treated as authenticating later, and the router lets the request through to it.

Must not raise; the router treats an exception here as "not authorized".

@callback handle_inbound(Plug.Conn.t()) :: Plug.Conn.t()

Handles a request routed to this adapter's registered segment.

Receives a Plug.Conn whose body has already been parsed by LemonChannels.InboundHttp.Router, and must return the conn having sent a response. Raising is caught by the router and answered with a 500.