code: func (pool *TxPool) lockedReset(oldHead, newHead *types.Header) {
  	pool.mu.Lock()
  	defer pool.mu.Unlock()
  
  	pool.reset(oldHead, newHead)
  }
docs: // lockedReset is a wrapper around reset to allow calling it in a thread safe
  // manner. This method is only ever used in the tester!