[lllr_finger]

Netflix's circuit breaking OSS project, Hystrix, is commonly seen alongside Ratpack/rxjava where both reactive streams and back pressure are in play. I don't think you're wrong, but Netflix and others using their solutions like Hystrix and Hollow, are outside of what I'd consider "usual" problems and solutions.

[nvarsj]

I don't think this library is meant to be used w/ reactive streams. It talks a lot about limiting number of concurrent threads, so it sounds more like traditional RPC with a request pool that they are trying to size to inform clients to back off (by returning 429).