What do the various ISubject implementations do and when would they be used?

Question

I have a fairly good idea of what the Subject class does and when to use it, but I\'ve just been looking through the language reference on msdn and see there are various other I

Answer 1

Paul's answer pretty much nails it. There's a few things worth adding, though:

AsyncSubject works as Paul says, but only after the source completes. Before that, it works like Subject (where "live" values are received by subscribers)

AsyncSubject has changed since I last ran tests against it. It no longer acts as a live subject before completion, but waits for completion before it emits a value. And, as Sergey mentions, it returns the last value, not the first (though I should have caught that as that's always been the case)

AsyncSubject is used by Prune, FromAsyncPattern, ToAsync and probably a few others

BehaviorSubject is used by overloads of Publish that accept an initial value

ReplaySubject is used by Replay

NOTE: All operator references above refer to the publishing set of operators as they were before they were replaced with generalised publish operators in rev 2838 (Christmas '10) as it has been mentioned that the original operators will be re-added