public Duration multiply(long amount) {
        return new Multiply().apply(this, unit == null ? FOREVER : new Duration(amount, unit));
    }
public Duration multiply(long amount) {
        return new Multiply().apply(this, unit == null ? FOREVER : new Duration(amount, unit));
    }
public Duration multiply ( long amount ) { return new Multiply ( ) . apply ( this , unit == null ? FOREVER : new Duration ( amount , unit ) ) ; }
Multiply this amount with the given amount

@param amount The amount
@return A new amount
Multiply this amount with the given amount