During development you may want to add a panel for the Yii2 debug module. The panel displays a counter and a list of queued tasks.
yiisoft/yii2-debug module should be installed in your application for the panel to be displayed.
Configure your application like the following:
return [ 'modules' => [ 'debug' => [ 'class' => \yii\debug\Module::class, 'panels' => [ 'queue' => \yii\queue\debug\Panel::class, ], ], ], ];