code: protected URI doPostCreateMultipart(String path, InputStream inputStream) throws ClientException {
          return doPostCreateMultipart(path, inputStream, null);
      }
docs: Creates a resource specified as a multi-part form in an input stream.
  Adds appropriate Accepts and Content Type headers.
  
  @param path the the API to call.
  @param inputStream the multi-part form content.
  @return the URI representing the created resource, for use in subsequent
  operations on the resource.
  @throws ClientException if a status code other than 200 (OK) and 201
  (Created) is returned.