Create a stub backend using the given response monad (which determines the effect type for responses), and any capabilities (such as streaming or web socket support).
Create a stub of an asynchronous backend (which uses the Scala's built-in Future as the effect type), without streaming.
Create a stub of a synchronous backend (which doesn't use an effect type), without streaming.
Create a stub backend which delegates send requests to the given fallback backend, if the request doesn't match any of the specified predicates.
(Since version ) see corresponding Javadoc for more information.