Question: Is there support for progress for transfers?

[jhoughjr]

I've done some looking and dont see any way to do what URLSessionTaskDelegate enables.

    	_ session: URLSession, 
        task: URLSessionTask, 
        didSendBodyData bytesSent: Int64, 
        totalBytesSent: Int64, 
        totalBytesExpectedToSend: Int64
     )```
Im brainstorming what the api might look like and how it could work.
I assume this all wraps URLSessionTask so it feels it should be doable, but I wanted your thoughts before I went far.