private boolean isMessageValid(final RoundChange msg) {
    return roundChangeMessageValidator.validateRoundChange(msg);
  }
Adds the round message to this manager and return a certificate if it passes the threshold

@param msg The signed round change message to add
@return Empty if the round change threshold hasn't been hit, otherwise a round change
    certificate
consensus/ibft/src/main/java/org/hyperledger/besu/consensus/ibft/statemachine/RoundChangeManager.java