Default HTTP adapter implementation using Req.
Observability
Passing a :plugins list as part of the adapter options lets the consuming application attach
custom Req steps for telemetry, logging, etc. that participate in the full request/response
pipeline:
%DSpace.API{
endpoint: "https://example.com/server",
http_impl: {DSpace.API.HTTP.Req, [plugins: [&MyApp.ReqTelemetry.attach/1]]}
}