Deferred services in Phalcon 3.

services.php

<?php

$di->set('deferred.classes', $deferred = [
    'mail.selected_adapter' => Closure,
    'mail' => Closure,
    'db' => Closure,
    'log' => Closure,
]);

function resolve($alias)
{
    if (!$di->has($alias)) {
        return $di->get($alias);
    }

    $deferred = $di->get('deferred.classes');

    if (isset($deffered[$alias])) {
        // Do the binding process manually register using:
        // $di->set($alias, call_user_func_array($callback, $params));

        return $di->get($alias);
    }

    throw new RuntimeException('Unable to resolve alias ['.$alias.'].');
}