code: protected InputStream getStreamFromOtherSource(String imageUri, Object extra) throws IOException {
  		throw new UnsupportedOperationException(String.format(ERROR_UNSUPPORTED_SCHEME, imageUri));
  	}
docs: Retrieves {@link InputStream} of image by URI from other source with unsupported scheme. Should be overriden by
  successors to implement image downloading from special sources.<br />
  This method is called only if image URI has unsupported scheme. Throws {@link UnsupportedOperationException} by
  default.
  
  @param imageUri Image URI
  @param extra    Auxiliary object which was passed to {@link DisplayImageOptions.Builder#extraForDownloader(Object)
  DisplayImageOptions.extraForDownloader(Object)}; can be null
  @return {@link InputStream} of image
  @throws IOException                   if some I/O error occurs
  @throws UnsupportedOperationException if image URI has unsupported scheme(protocol)