add async iterator

[zh99998]

https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-3.html the new Async Iteration syntax is great how about make observables async iteratable? for await (const item of an_observable) { ... }

here is a implement https://gist.github.com/zenparsing/4e65592f184dafc82125

[paulpdaniels]

I think you should have a look at https://github.com/ReactiveX/IxJS. Async iterators might be a better fit there. Additionally this repo is in maintenance mode and will not be accepting new features.