Streaming uploads

[tve]

It would be helpful for requests to support a Stream as the request body. I believe this is actually fairly simple, in that the query function needs to distinguish a StreamReader parameter and then send needs to use Stream.pipeline to connect the reader and request writer. Node.js' HTTP does the chunking automatically. At least that's my theory of how it would work ;-)
NB: I was trying to use phin, so ensuring phin can use this would be good too, I believe it just passes the data field through, so that should be automatic.