code: protected void upload(final File file, final ProgressListener progressListener, ResponseListener responseListener) {
          String contentTypeHeader = headers.get(CONTENT_TYPE);
          final String contentType = contentTypeHeader != null ? contentTypeHeader : BINARY_CONTENT_TYPE;
  
          RequestBody body = RequestBody.create(MediaType.parse(contentType), file);
          // Custom RequestBody wrapper that monitors the progress of the upload
  
          ProgressRequestBody progressBody = new ProgressRequestBody(file, body, progressListener);
  
          sendRequest(null, responseListener, progressBody);
      }
docs: Upload a file asynchronously.
  If the Content-Type header was not previously set, this method will set it to "application/octet-stream".
  
  @param file              The file to upload
  @param progressListener  The listener that monitors the upload progress
  @param responseListener  The listener whose onSuccess or onFailure methods will be called when this request finishes