code: protected Response upload(String name, File fileToUpload, String mediaTypeString, Object... pathArgs) throws IOException {
          URL url = getApiUrl(pathArgs);
          return (upload(name, fileToUpload, mediaTypeString, null, url));
      }
docs: Perform a file upload using the specified media type, returning
  a ClientResponse instance with the data returned from the endpoint.
  
  @param name the name for the form field that contains the file name
  @param fileToUpload a File instance pointing to the file to upload
  @param mediaTypeString the content-type of the uploaded file, if null will be determined from fileToUpload
  @param pathArgs variable list of arguments used to build the URI
  @return a ClientResponse instance with the data returned from the endpoint
  @throws IOException if an error occurs while constructing the URL