Implement 413 - Payload Too Large

[azertyalex]

Is your feature request related to a problem? Please describe. I need a way to notify my API users that the uploaded file is too large, before it is being uploaded completely.content_size_limit isn't what I need.

Describe the solution you'd like I'd like to set a file size limit. Returning a 413 with Payload Too Large before it being uploaded completely

Describe alternatives you've considered I can't use a reverseproxy because of the configurability in my app.