@VisibleForTesting
  public static Bytes encodeForEth68(
      final List<TransactionType> types, final List<Integer> sizes, final List<Hash> hashes) {

    final byte[] byteTypes = new byte[types.size()];
    for (int i = 0; i < types.size(); i++) {
      final TransactionType type = types.get(i);
      byteTypes[i] = type.getEthSerializedType();
    }
    return encodeForEth68(byteTypes, 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