code: func (mp *TxPool) RemoveOrphan(tx *btcutil.Tx) {
  	mp.mtx.Lock()
  	mp.removeOrphan(tx, false)
  	mp.mtx.Unlock()
  }
docs: // RemoveOrphan removes the passed orphan transaction from the orphan pool and
  // previous orphan index.
  //
  // This function is safe for concurrent access.