private static Bytes encode(
      final Bytes vanityData,
      final List<Address> validators,
      final Optional<SECPSignature> proposerSeal) {
    final Bytes validatorData = Bytes.concatenate(validators.toArray(new Bytes[0]));
    return Bytes.concatenate(
        vanityData,
        validatorData,
        proposerSeal
            .map(SECPSignature::encodedBytes)
            .orElse(Bytes.wrap(new byte[SECPSignature.BYTES_REQUIRED])));
  }
Encode unsealed to bytes.

@param vanityData the vanity data
@param validators the validators
@return the bytes
consensus/clique/src/main/java/org/hyperledger/besu/consensus/clique/CliqueExtraData.java