Support chunked transfer encoding

[clue]

See https://tools.ietf.org/html/rfc7230#section-3.3.1 and https://tools.ietf.org/html/rfc7230#section-3.3

[WyriHaximus]

FYI we support it from our side to the client but not the other way around yet: https://github.com/reactphp/http/blob/master/src/Response.php#L99-L105

[clue]

Thanks for linking to this, FWIW, this has been implemented in the HttpClient component via reactphp/http-client#58

[clue]

I hear @legionth may be working on this feature currently, perhaps he can chime in here? 😀

[legionth]

Yes, I'm currently working on this. Because the client and server component are currently seperated (and I think this won't change in the next days), I would consider to put a chunked encoder and decoder into this package. Even if this would lead to a duplication.

I will check if this reactphp/http-client#58 or this https://github.com/legionth/php-http-server-react/blob/master/src/ChunkedDecoder.php is better to use in my current work.