Implement `(source, source) -> stage -> sink` test
Implement `(source, source) -> stage -> sink` test

DavadDi/actor-framework,DavadDi/actor-framework,actor-framework/actor-framework,DavadDi/actor-framework,actor-framework/actor-framework,DavadDi/actor-framework,actor-framework/actor-framework,actor-framework/actor-framework