@Override
  public @Nullable NewVirtualFile findFileById(int fileId) {
    if (fileId == FSRecords.NULL_FILE_ID) {
      fileByIdCacheHits.incrementAndGet();  //a bit of a stretch, but...
      return null;
    }
    VirtualFileSystemEntry cached = myIdToDirCache.getCachedDir(fileId);
    if (cached != null) {
      fileByIdCacheHits.incrementAndGet();
      return cached;
    }

    fileByIdCacheMisses.incrementAndGet();
    ParentFinder finder = new ParentFinder();
    return finder.find(fileId);
  }
@Override
  public @Nullable NewVirtualFile findFileById(int fileId)