public @Nullable VirtualFile findChild(@NotNull @NonNls String name) {
    VirtualFile[] children = getChildren();
    if (children == null) return null;
    for (VirtualFile child : children) {
      if (child.nameEquals(name)) {
        return child;
      }
    }
    return null;
  }
public @Nullable VirtualFile findChild(@NotNull @NonNls String name)