public static function start($alias)
    {
        if (isset(self::$timers[$alias])) {
            throw new \RuntimeException('Timer has already been started.');
        }

        self::$timers[$alias] = microtime();
    }
public static function start($alias)
    {
        if (isset(self::$timers[$alias])) {
            throw new \RuntimeException('Timer has already been started.');
        }

        self::$timers[$alias] = microtime();
    }
public static function start ( $ alias ) { if ( isset ( self :: $ timers [ $ alias ] ) ) { throw new \ RuntimeException ( 'Timer has already been started.' ) ; } self :: $ timers [ $ alias ] = microtime ( ) ; }
Starts timer.

@param $alias

@throws \RuntimeException
Starts timer .