@Override
  public void onNewUnverifiedForkchoice(final ForkchoiceEvent event) {
    if (event.hasValidFinalizedBlockHash()) {
      stop();
    }
  }
Try to request the lowest ancestor for the given pending block or process the descendants if
the ancestor is already in the chain
ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/sync/BlockPropagationManager.java