code: public void setExplodedAppDirectory(File explodedAppDirectory) {
      this.explodedAppDirectory = explodedAppDirectory;
      into(explodedAppDirectory);
      preserve(
          patternFilterable ->
              patternFilterable.include("WEB-INF/appengine-generated/datastore-indexes-auto.xml"));
    }
docs: Sets the output directory of Sync Task and preserves the setting so it can be recovered later
  via getter.