@Override
  public boolean submitHashRate(final String id, final Long hashrate) {
    if (hashrate == 0) {
      return false;
    }
    LOG.info("Hashrate submitted id {} hashrate {}", id, hashrate);
    sealerHashRate.put(id, hashrate);
    return true;
  }
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