Readme: Compare to Rx/IObservable/Ix/AsyncEnumerable

[boekabart]

I think it'd be good to have a section or separate document that highlights the differences with the existing Rx/Ix for .Net - a lot of interested people are bound to have experience with that and might be confused with how this is different.

[macsux]

Second. I had a lot of exposure to Reactive Extensions, though this seems more advanced with back pressure features which RX is lacking. I only learned of this project from looking at Akka

[boekabart]

Some (including me) would argue that RX isn't lacking backpressure at all: there's Ix for consumer-paced psuedo-reactive pipelines.
Reactive-Streams is, by design, a hybrid between those two, or actually, much like Ix but with batch-requests :)

[cecilphillip]

I came across this issue when looking for just such a comparison. The next, error, complete semantics seems pretty similar. Some use case examples would be great.

[marcpiechura]

There is a long discussion about RX/IX and Reactive.Streams in the RX.Net repository and you can take a look at #19, maybe that helps.

Long story short, the way I see it is that Reactive.Streams provide the push behavior from RX + the back pressure from IX without the additional cost of allocating a Task per item. Furthermore it's switching between push/pull behavior dynamically at runtime depending on how fast your producer/consumer is.