protected double parseDouble(String string) {
    try {
      return Double.parseDouble(string);
    } catch (Exception e) {
      return -1.0;
    }
  }
format 1.536834943435905E12 (nano seconds) to 1536834943435 (ms)
and convert timestamp to milliseconds

@param s raw String obtained from getStats.

@return the formatted timestamp
KITE-Framework/src/main/java/org/webrtc/kite/stats/rtc/RTCSingleStatObject.java