@Override
    public @Nullable Boolean readIfActual(VirtualFile vFile) throws IOException {
      long stamp = vFile.getTimeStamp();
      long fieldValue = storageHelper.readLongField(vFile, 0);

      //use sign bit to store true(1) | false(0)
      long timestamp = Math.abs(fieldValue);
      boolean value = fieldValue < 0;

      if (timestamp == stamp) {
        return value;
      }
      else {
        return null;
      }
    }
@Override
    public @Nullable Boolean readIfActual(VirtualFile vFile)