@Override
  public Optional<Long> hashesPerSecond() {
    if (sealerHashRate.size() <= 0) {
      return localHashesPerSecond();
    } else {
      return remoteHashesPerSecond();
    }
  }
Responsible for determining when a block mining operation should be started/stopped, then
creating an appropriate miner and starting it running in a thread.
ethereum/blockcreation/src/main/java/org/hyperledger/besu/ethereum/blockcreation/PoWMiningCoordinator.java