[Feature request] AsyncElasticsearch should implement an async context manager

[amandasystems]

It would be nice if AsyncElasticsearch implemented the magic methods (specifically __aenter__() and __aexit__()) to become an async context manager, which would allow code like this:

async with AsyncElasticsearch() as client:
    print(await client.info()) 

and have the session closed.

Happy to implement this similar to how aiohttp has done it if you are interested!

[fxdgear]

@AlbinS If you write it I'll review it! :)

Thanks

[amandasystems]

@fxdgear Great; I'll start working on it then!