code: func fetchMempoolTxnsForAddress(s *rpcServer, addr btcutil.Address, numToSkip, numRequested uint32) ([]*btcutil.Tx, uint32) {
  	// There are no entries to return when there are less available than the
  	// number being skipped.
  	mpTxns := s.cfg.AddrIndex.UnconfirmedTxnsForAddress(addr)
  	numAvailable := uint32(len(mpTxns))
  	if numToSkip > numAvailable {
  		return nil, numAvailable
  	}
  
  	// Filter the available entries based on the number to skip and number
  	// requested.
  	rangeEnd := numToSkip + numRequested
  	if rangeEnd > numAvailable {
  		rangeEnd = numAvailable
  	}
  	return mpTxns[numToSkip:rangeEnd], numToSkip
  }
docs: // fetchMempoolTxnsForAddress queries the address index for all unconfirmed
  // transactions that involve the provided address.  The results will be limited
  // by the number to skip and the number requested.