code: func (mp *TxPool) IsOrphanInPool(hash *chainhash.Hash) bool {
  	// Protect concurrent access.
  	mp.mtx.RLock()
  	inPool := mp.isOrphanInPool(hash)
  	mp.mtx.RUnlock()
  
  	return inPool
  }
docs: // IsOrphanInPool returns whether or not the passed transaction already exists
  // in the orphan pool.
  //
  // This function is safe for concurrent access.