@Override
  // The coinbase field is used for voting nodes in/out of the validator group. However, no votes
  // are allowed to be cast on epoch blocks
  public boolean validate(final BlockHeader header, final BlockHeader parent) {
    if (epochManager.isEpochBlock(header.getNumber())
        && !header.getCoinbase().equals(CliqueBlockInterface.NO_VOTE_SUBJECT)) {
      LOG.info(
          "Invalid block header: No clique in/out voting may occur on epoch blocks ({})",
          header.getNumber());
      return false;
    }
    return true;
  }
Instantiates a new Coinbase header validation rule.

@param epochManager the epoch manager
consensus/clique/src/main/java/org/hyperledger/besu/consensus/clique/headervalidationrules/CoinbaseHeaderValidationRule.java