public static String format(Duration duration, boolean concise) {
        return format(duration, concise, Integer.MAX_VALUE);
    }
Formats {@code duration} as a string, either in a {@code concise} (1 letter)
or full length format, displaying all possible elements.

@param duration the duration
@param concise  if the output should be concisely formatted
@return the formatted string
helper/src/main/java/me/lucko/helper/time/DurationFormatter.java