private static Optional<RoundChangeCertificate> readRoundChangeCertificate(final RLPInput rlpIn) {
    RoundChangeCertificate roundChangeCertificate = null;
    if (!rlpIn.nextIsNull()) {
      roundChangeCertificate = RoundChangeCertificate.readFrom(rlpIn);
    } else {
      rlpIn.skipNext();
    }

    return Optional.ofNullable(roundChangeCertificate);
  }
Decode.

@param data the data
@return the proposal
consensus/ibft/src/main/java/org/hyperledger/besu/consensus/ibft/messagewrappers/Proposal.java