@Override
  public long lastUpdate() {
    return undoLog.isEmpty() ? 0L : undoLog.get(undoLog.size() - 1).level;
  }
Create an UndoSet backed by another Set instance.

@param delegate The Set instance to use for backing storage
@param <V> The type of the collection.
@return an unduable set
evm/src/main/java/org/hyperledger/besu/collections/undo/UndoSet.java