     - Encoded file data
     - Multipart form boundary
 */
-public struct FileURLForMultipartFormData: MultipartFormData {
+public class FileURLForMultipartFormData: MultipartFormData {
     let fileURL: NSURL
     let fileName: String?
     let mimeType: String?

}

/**
    Helps to encode multipart-form-data's body part from the file.

    The body part data will be encoded using the following format:


    /**
        - parameter fileURL: The URL of the file whose content will be encoded into the multipart form data.
    */
    public init(fileURL: NSURL) {
        self.fileURL = fileURL

        self.fileName = nil
