docs: private static String readLineFromReaderWithoutMark(Reader input)
              throws IOException {
  
          int c = input.read();
          if (c == -1)
              return null;
          StringBuilder line = new StringBuilder(expectedLineLength);
  
          while (c != EOF && c != '\n' && c != '\r') {
              char ch = (char) c;
              line.append(ch);
              c = input.read();
          }
          return line.toString();
      }