code: public OpenFileInfo[] iterativeGetOpenFiles(
      String prefix, int millis, String start) {
      return leaseManager.iterativeGetOpenFiles(prefix, millis, start);
    }
docs: Fetch the list of files that have been open longer than a
  specified amount of time.
  @param prefix path prefix specifying subset of files to examine
  @param millis select files that have been open longer that this
  @param where to start searching, or null
  @return array of OpenFileInfo objects
  @throw IOException