@Override
  public long getChainHeight() {
    return parentHeader.getNumber() + 1;
  }
If the list of validators for the next block to be proposed/imported has changed from the
previous block, log the change. Only log for round 0 (i.e. once per block).

@param ibftRound The current round
consensus/ibft/src/main/java/org/hyperledger/besu/consensus/ibft/statemachine/IbftBlockHeightManager.java