Right now there is no way to call Body#formData on arbitrary user input without potentially causing an OOM. It would be great if we could constrain the formData parser so it stops parsing if a body exceeds a certain size.

Example API:

const form = req.formData({ maxSize: 10_000_000 /* 10MB */ })

If the body size exceeds the max size, a QuotaExceededError DOMException should be thrown.

This might make sense for .text(), .blob(), .arrayBuffer(), and .json() also.