src/Shared/Extension/ExtensionAwareTrait.php
protected function runExtension(/*# string */ $method, array $args)
    {
        /* @var $ext ExtensionInterface */
        $ext = $this->extension_methods[$method];

        // execute extesion method
        return call_user_func_array([$ext, $method], $args);
    }
protected function runExtension(/*# string */ $method, array $args)
    {
        /* @var $ext ExtensionInterface */
        $ext = $this->extension_methods[$method];

        // execute extesion method
        return call_user_func_array([$ext, $method], $args);
    }
Include this in server's __call()

@param  string $method
@param  array $args
@return mixed
@access protected