fetchText method
Fetch content body as text from a resource identified by reference.
Depending on the API the reference can be a relative path, an absolute
URL, a key, or other identifier relevant on a context of an API.
Throws an ApiException if fetching fails. Implementations like HTTP
fetcher may also throw other status codes than codes for success as
exceptions.
Implementation
@override
Future<String> fetchText(Uri reference) async =>
(await fetch(reference)).text;