code: func (mp *TxPool) RemoveOrphansByTag(tag Tag) uint64 {
  	var numEvicted uint64
  	mp.mtx.Lock()
  	for _, otx := range mp.orphans {
  		if otx.tag == tag {
  			mp.removeOrphan(otx.tx, true)
  			numEvicted++
  		}
  	}
  	mp.mtx.Unlock()
  	return numEvicted
  }
docs: // RemoveOrphansByTag removes all orphan transactions tagged with the provided
  // identifier.
  //
  // This function is safe for concurrent access.