Coming in 2.3, we will have full capabilities for backpressure. We already have window/buffer/throttle, etc. But, I think it's naive to have only one style of backpressure because many are valid. Just an example of RxJS, and what can be done, which includes a style in which you can do several forms of backpressure, and yes, push to pull based models: https://gist.github.com/mattpodwysocki/9010149

Still fleshing it out, but pretty close to calling it complete: https://github.com/Reactive-Extensions/RxJS/tree/master/src/...

We're more than open to pull requests though if anyone thinks we're missing something here.