Only happens in HTTPS because seemingly somewhere in the stack up to
50mb of data is being buffered potentially triggering a timeout at a
higher level if not drained fast enough.
This commit also includes other streams related improvements.
This also fixes a memory leak issue when the client disconnects before
completing the download. I suspect the leak had something to do with
using pipe() but I'm not sure if it's a bug in MongoDB driver or that
we were lacking proper error handling. Anyway, the pipe is no longer
leaking :)
Zaid Humaimidi
Clément Hampaï
Shweelan Samson