Provide analogue of AsyncSeq.combineLatest

[pkese]

See https://fsprojects.github.io/FSharp.Control.AsyncSeq/reference/fsharp-control-asyncseq.html#combineLatest

Merges two async sequences. The resulting async sequence produces an element when either input sequence produces an element, passing the new element from the emitting sequence and the previously emitted element from the other sequence. If either of the input sequences is empty, the resulting sequence is empty.

[pkese]

Ah, I was actually thinking of merge ... so that is also missing.

https://fsprojects.github.io/FSharp.Control.AsyncSeq/reference/fsharp-control-asyncseq.html#merge

Merges two async sequences of the same type into an async sequence non-deterministically. The resulting async sequence produces elements when any argument sequence produces an element.