As defined in PSR-7, the `getBody()` method returns a stream instance which implements the [PSR-7 StreamInterface](http://www.php-fig.org/psr/psr-7/#psrhttpmessagestreaminterface).
Note that the incoming request will be processed once the request headers have been received, which implies that the (potentially much larger) request body may still be outstanding (in a streaming state).
However, most of the `PSR-7 StreamInterface` methods have been designed under the assumption of being in control of the request body.
Given that this does not apply to this server, the following `PSR-7 StreamInterface` methods are not used and SHOULD NOT be called:
`tell()`, `eof()`, `seek()`, `rewind()`, `write()` and `read()`.
Instead, the returned stream instance *also* implements the [ReactPHP ReadableStreamInterface](https://github.com/reactphp/stream#readablestreaminterface) which gives you access to the incoming request body as the individual chunks arrive: