Encodes the response with the encoding that is requested by the client via the ``Accept-Encoding`` header or rejects the request with an ``UnacceptedResponseEncodingRejection(supportedEncodings)``.
The response encoding is determined by the rules specified in RFC7231_.
If the ``Accept-Encoding`` header is missing or empty or specifies an encoding other than identity, gzip or deflate then no encoding is used.