rest-client/rest-client — pull request #222 by shark-src (2013-08-23 17:18:34+00:00)
Title: Support for content-type in each of multi-part rquest

This allows users to specify content-type in payload like,
RestClient.post(url, {data: "something", content_type: "text/plain"})

Some Rest servers check for content type in each part before taking doing anything with the data in part.
This option will only be honored with multipart option enabled.