private static FileType[] findFileTypeByRel(@Nullable String rel) {
    if (rel == null) return null;
    for (String type : rel.split(" ")) {
      if ("stylesheet".equalsIgnoreCase(type)) {
        return findFileType("text/css");
      }
      if (type.contains("icon") || type.contains("image")) {
        return IMAGE_FILE_TYPES.get();
      }
    }
    return null;
  }
private static FileType[] findFileTypeByRel(@Nullable String rel)