code: public String getElapsedTimeString() {
          int elapsedSeconds = (int) (getElapsedTime() / 1000);
  
          if (elapsedSeconds == 0)
              return "0s";
  
          int minutes = elapsedSeconds / 60;
          elapsedSeconds -= (60 * minutes);
  
          if (minutes == 0) {
              return elapsedSeconds + "s";
          }
  
          return minutes + "m " + elapsedSeconds + "s";
      }
docs: Gets the elapsed time as a string, expressed in seconds if the value is {@code < 60},
  or expressed in minutes:seconds if the value is {@code >=} 60.
  @return string representation of the elapsed time