public static int minutesOf(long duration) {
        return (int) duration / MILLIS_PER_MINUTE;
    }
Calculates the full number of minutes within the specified duration.

@param duration duration in milliseconds
@return number of minutes within the specified duration.
android/third_party/time-duration-picker/src/main/java/mobi/upod/timedurationpicker/TimeDurationUtil.java