code: @Override
    public Extractor<S, D> getExtractor(WorkUnitState state) throws IOException {
      Preconditions.checkNotNull(state, "WorkUnitState should not be null");
      LOG.info("WorkUnitState from getExtractor: " + state);
  
      try {
        //GoogleDriveExtractor needs GoogleDriveFsHelper
        initFileSystemHelper(state);
      } catch (FileBasedHelperException e) {
        throw new IOException(e);
      }
  
      Preconditions.checkNotNull(fsHelper, "File system helper should not be null");
      return new GoogleDriveExtractor<>(state, fsHelper);
    }
docs: As Google Drive extractor needs file system helper, it invokes to initialize file system helper.
  {@inheritDoc}
  @see org.apache.gobblin.source.Source#getExtractor(org.apache.gobblin.configuration.WorkUnitState)