@Override
  public boolean isValidMessageCode(final int protocolVersion, final int code) {
    switch (code) {
      case IbftV2.PROPOSAL:
      case IbftV2.PREPARE:
      case IbftV2.COMMIT:
      case IbftV2.ROUND_CHANGE:
        return true;

      default:
        return false;
    }
  }
Get ibft sub protocol.

@return the ibft sub protocol
consensus/ibft/src/main/java/org/hyperledger/besu/consensus/ibft/protocol/IbftSubProtocol.java