pass field directly for files

[gurgunday]

Closes #472

Instead of monkey patching request.file() and making it return already consumed file fields, we can just pass them directly to req.body when attachFieldsToBody is set to 'keyValues'

Initially, this PR only passed _buf and filename, but if someone needs to see the file name, they might also want to see the mimetype or other properties, so we now just pass the entire field for files

Checklist

• run npm run test and npm run benchmark
• tests and/or benchmarks are included
• documentation is changed or added
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct

[Uzlopak]

Sounds semver major

[gurgunday]

Yeah, I pointed it at next

[gurgunday]

This also lets people use the registered schema to validate file properties, which otherwise is redundant for attachFieldsToBody: 'keyValues'

[mcollina]

lgtm

[gurgunday]

This PR will be superseded

[ryanrishi]

@gurgunday was this PR ever superseded by another PR? I'm looking to get both the filename and contents while using attachFieldsToBody: 'keyValues', so this change would still be very helpful.

[sourabh-goyal-kasitech]

is this available now?

[gurgunday]

Hey, this is still not available

Feel free to send a PR to next — you can just pass the file field instead of calling toBuffer like in this PR

I'm trying to write a performant multipart/form-data parser currently