code: func (cl *Client) WaitAll() bool {
  	cl.lock()
  	defer cl.unlock()
  	for !cl.allTorrentsCompleted() {
  		if cl.closed.IsSet() {
  			return false
  		}
  		cl.event.Wait()
  	}
  	return true
  }
docs: // Returns true when all torrents are completely downloaded and false if the
  // client is stopped before that.