Created by: Teyras
The current master converts anything that is not FormData to JSON. This behavior causes operations that accept a file to send requests where the payload is an empty JSON object.
This PR adds another branch that lets Blobs pass without modification.
@TiFu (2017/07) @taxpon (2017/07) @sebastianhaas (2017/07) @kenisteward (2017/07) @Vrolijkx (2017/09) @macjohnny (2018/01) @nicokoenig (2018/09) @topce (2018/10)