• Ensure a correct Content-Disposition header is included in every part of a multipart message. #2451
• Added MultipartError::NoContentDisposition variant. #2451
• Since Content-Disposition is now ensured, Field::content_disposition is now infallible. #2451
• Added Field::name method for getting the field name. #2451
• MultipartError now marks variants with inner errors as the source. #2451
• MultipartError is now marked as non-exhaustive. #2451