private static Bytes encodeForEth66(final List<Transaction> transactions) {
    final BytesValueRLPOutput out = new BytesValueRLPOutput();
    out.writeList(toHashList(transactions), (h, w) -> w.writeBytes(h));
    return out.encoded();
  }
Encode a list of hashes for the NewPooledTransactionHashesMessage using the Eth/66

<p>format: [hash_0: B_32, hash_1: B_32, ...]

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