RequestContent is the most important interceptor for outgoing requests.
It is responsible for delimiting content length by adding
Transfer-Content headers based
on the properties of the enclosed entity and the protocol version.
This interceptor is required for correct functioning of client side protocol
Processes a request.
On the client side, this step is performed before the request is
sent to the server. On the server side, this step is performed
on incoming messages before the message body is evaluated.
||the request to preprocess
||the context for the request