@Override
  public Bytes encode() {
    final BytesValueRLPOutput rlpOut = new BytesValueRLPOutput();
    rlpOut.startList();
    getSignedPayload().writeTo(rlpOut);
    proposedBlock.writeTo(rlpOut);
    if (roundChangeCertificate.isPresent()) {
      roundChangeCertificate.get().writeTo(rlpOut);
    } else {
      rlpOut.writeNull();
    }
    rlpOut.endList();
    return rlpOut.encoded();
  }
Gets round change certificate.

@return the round change certificate
consensus/ibft/src/main/java/org/hyperledger/besu/consensus/ibft/messagewrappers/Proposal.java