Is there a way to trace responses from two or more "fire" ?

Thinking there maybe another "fire" on an event is firing:

class DemoListener {
    public __construct($di) {
        $this->di = $di;
    }

    public function demoHandler(){
        $this->di['eventsManager']->fire("another:handler", $this);
    }
}

$this->eventsManager->attach('demo', new DemoListener($this->di));

$this->eventsManager->fire("demo:demoHandler", $this)

Now, if I want getting responses from demo and another, how ?