@ApiStatus.Internal
  public void setCaseSensitivityFlag(@NotNull FileAttributes.CaseSensitivity sensitivity) {
    if (sensitivity == FileAttributes.CaseSensitivity.UNKNOWN) {
      throw new IllegalArgumentException("invalid argument for " + this + ": " + sensitivity);
    }
    VfsData vfsData = getVfsData();
    VfsData.Segment segment = vfsData.getSegment(getId(), false);
    int newFlags = VfsDataFlags.CHILDREN_CASE_SENSITIVITY_CACHED |
                   (sensitivity == FileAttributes.CaseSensitivity.SENSITIVE ? VfsDataFlags.CHILDREN_CASE_SENSITIVE : 0);
    segment.setFlags(getId(), VfsDataFlags.CHILDREN_CASE_SENSITIVE | VfsDataFlags.CHILDREN_CASE_SENSITIVITY_CACHED, newFlags);
  }
@ApiStatus.Internal
  public void setCaseSensitivityFlag(@NotNull FileAttributes.CaseSensitivity sensitivity)