@Override
  public void force(boolean metaData) throws IOException {
    checkOpen();

    // nothing to do since writes are all direct to the storage
    // however, we should handle the thread being interrupted anyway
    boolean completed = false;
    try {
      begin();
      completed = true;
    } finally {
      end(completed);
    }
  }
Ends a blocking operation, throwing an exception if the thread was interrupted while blocking
or if the channel was closed from another thread.
jimfs/src/main/java/com/google/common/jimfs/JimfsFileChannel.java