private static Bytes encodeForEth68(final List<Transaction> transactions) {
    final List<Integer> sizes = new ArrayList<>(transactions.size());
    final byte[] types = new byte[transactions.size()];
    final List<Hash> hashes = new ArrayList<>(transactions.size());

    for (int i = 0; i < transactions.size(); i++) {
      final TransactionType type = transactions.get(i).getType();
      types[i] = type.getEthSerializedType();
      sizes.add(transactions.get(i).getSize());
      hashes.add(transactions.get(i).getHash());
    }

    return encodeForEth68(types, sizes, hashes);
  }
Encode a list of transactions for the NewPooledTransactionHashesMessage using the Eth/68

<p>format: [[type_0: B_1, type_1: B_1, ...], [size_0: P, size_1: P, ...], ...]

@param transactions the list to encode
@return the encoded value. The message data will contain hashes, types and sizes.
ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/encoding/TransactionAnnouncementEncoder.java