docs: @SuppressWarnings("DefaultCharset")
      public static String readFileOrThrow(File file) throws IOException {
          try (Reader reader = new FileReader(file)) {
              char[] buf = new char[8192];
              int len;
              StringBuilder s = new StringBuilder();
              while ((len = reader.read(buf)) >= 0) {
                  s.append(buf, 0, len);
              }
              return s.toString();
          }
      }