streamed request / response not handled correctly

[Deltachaos]

In src/RequestHandler.php#L195 streams are not handled correctly for the request body. Also in the response conversion, the streams get lost.

In symfony/psr-http-message-bridge, there is correct handling for streams.

[mmoreram]

Missing Streamed requests.

Implemented Streamed responses here - 3ed8edb

[mmoreram]

Opened a more specific Streamed requests Issue here - #53

Please, if you have ideas about how to implement that, don't hesitate to comment there.

Thanks!