src/Worker.php
function refTask(\CharlotteDunois\Phoebe\AsyncTask $task) {
        if(!isset($this->refBag[$task->id])) {
            $this->refBag[$task->id] = \time();
            $this->bag->currentlyBusy = true;
        }
    }
function refTask(\CharlotteDunois\Phoebe\AsyncTask $task) {
        if(!isset($this->refBag[$task->id])) {
            $this->refBag[$task->id] = \time();
            $this->bag->currentlyBusy = true;
        }
    }
References a task. Increments the worker's busy counter and keeps the worker busy
until the task dereferences. This method should be called by the user, if the async task
is entirely asynchronous and thus does not finish in the same loop iteration (aka sync).
@param \CharlotteDunois\Phoebe\AsyncTask  $task
@return void