Why no trim_whitespace option on RelatedField and SlugRelatedField?

[lionelbrits]

I was disappointed to see that I can't specify trim_whitespace=true on SlugRelatedField so that if my JSON comes in with trailing whitespace the system returns a "not found", so I have to patch the incoming data manually in get_serializer() instead, which seems inelegant. I guess DRF is pretty much frozen now, so this probably isn't going to change, but it would be nice to have this like CharField has.