public function start()
    {
        foreach ($this->items as $run) {
            if (!$run->hasStarted()) {
                $run->start();
            }
        }
        return $this;
    }
public function start()
    {
        foreach ($this->items as $run) {
            if (!$run->hasStarted()) {
                $run->start();
            }
        }
        return $this;
    }
public function start ( ) { foreach ( $ this -> items as $ run ) { if ( ! $ run -> hasStarted ( ) ) { $ run -> start ( ) ; } } return $ this ; }
Start all non running children

@return $this

@throws \Graze\ParallelProcess\Exceptions\NotRunningException
Start all non running children