@Override
    public synchronized String toString() {
      return "ProcessingBlocksManager{"
          + "importingBlocks="
          + importingBlocks
          + ", requestedBlocks="
          + requestedBlocks
          + ", requestedNonAnnouncedBlocks="
          + requestedNonAnnouncedBlocks
          + '}';
    }
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