code: func (pm *ProtocolManager) syncTransactions(p *peer) {
  	var txs types.Transactions
  	pending, _ := pm.txpool.Pending()
  	for _, batch := range pending {
  		txs = append(txs, batch...)
  	}
  	if len(txs) == 0 {
  		return
  	}
  	select {
  	case pm.txsyncCh <- &txsync{p, txs}:
  	case <-pm.quitSync:
  	}
  }
docs: // syncTransactions starts sending all currently pending transactions to the given peer.