code: boolean seemsLikeADirectoryAndUsePseudoDirectories(Storage storage) {
      if (!fileSystem.config().usePseudoDirectories()) {
        return false;
      }
      if (path.seemsLikeADirectory()) {
        return true;
      }
      // fancy case: the file name doesn't end in slash, but we've been asked to have pseudo dirs.
      // Let's see if there are any files with this prefix.
      if (storage == null) {
        // we are in a context where we don't want to access the storage, so we conservatively
        // say this isn't a directory.
        return false;
      }
      // Using the provided path + "/" as a prefix, can we find one file? If so, the path
      // is a directory.
      String prefix = path.removeBeginningSeparator().toString();
      if (!prefix.endsWith("/")) {
        prefix += "/";
      }
      Page<Blob> list =
          storage.list(
              this.bucket(),
              Storage.BlobListOption.prefix(prefix),
              // we only look at the first result, so no need for a bigger page.
              Storage.BlobListOption.pageSize(1),
              fileSystem.provider().getProject() == null
                  ? null
                  : Storage.BlobListOption.userProject(fileSystem.provider().getProject()));
      for (Blob b : list.getValues()) {
        // if this blob starts with our prefix and then a slash, then prefix is indeed a folder!
        if (b.getBlobId() == null) {
          continue;
        }
        String name = b.getBlobId().getName();
        if (name == null) {
          continue;
        }
        if (("/" + name).startsWith(this.path.toAbsolutePath() + "/")) {
          return true;
        }
      }
      // no match, so it's not a directory
      return false;
    }
docs: 2) (optional, if storage is set) is there a file whose name starts with path+/ ?