I didn't read the paper yet, but this thing of "composable distributed processing" made me think of Elixir's `GenStage`[0], which is still in development.
Another thing, that is indeed linked on GenStage's page as a reference, is Lasp language [1].
If anyone knows more about this stuff, and could say if these cited things are even related, it would be cool to hear.
[0] https://github.com/elixir-lang/gen_stage - "GenStage is a specification for exchanging events between producers and consumers."