example.php

<?php
class Hello
{
    protected $signal;
    
    // more deps
    public function __construct(Signal $signal)
    {
        $this->signal = $signal;
        // add handler
        $this->signal->handler($this, 'pre_action', [$this, 'preAction']);
    }
    
    // Eg : https://github.com/auraphp/Aura.Signal
    public function preAction()
    {
        
    }
    // more setters
}

$di->params['Hello']['signal'] = $di->lazyGet('signal');