Consider implementing HttpBody for Request and Response #2067
Description
In hyperium/http#107, we didn't implement Stream for http::{Request, Response} so as to not have the external dependency. However, in http-body, since we define the trait and import http, we could provide this implementation.
It'd make these slightly nicer:
while let Some(data) = req.data().await {}
let buf = hyper::body::aggregate(req);