The bring-your-own HTTP seam.

The library never depends on a third-party HTTP client. It defines this one callback and ships thinwrap_location_httpc (OTP httpc) as the default. To use hackney, gun, Finch, … implement the behaviour and pass it in the config:

Config = #{provider => google, api_key => Key,
           transport => {my_hackney_transport, #{pool => maps}}}.

request/2 sends one request and returns one response. Rules:

• A non-2xx answer is a response, never an error: return {ok, #{status := 404, ...}}. The connector owns status-to-error mapping.
• Return {error, timeout} (or any term containing the atom timeout) when the request timed out, so callers get the timeout code rather than provider_unavailable.
• Any other {error, Reason} is reported as provider_unavailable. The reason is rendered to a redacted string; it is never returned as a term, because a client's error may embed the request URL and its credentials.
• {error, {connector_error, Error}} surfaces a ready-made thinwrap_location:connector_error/0 unchanged (the default transport uses it to refuse non-https URLs).
• Never follow redirects: a 3xx must come back as a response, or the provider's credentials would be re-sent to wherever it points.