code: func (p *peer) SendTransactions(txs types.Transactions) error {
  	for _, tx := range txs {
  		p.knownTxs.Add(tx.Hash())
  	}
  	return p2p.Send(p.rw, TxMsg, txs)
  }
docs: // SendTransactions sends transactions to the peer and includes the hashes
  // in its transaction hash set for future reference.