t.php

<?php

class Middleware
{
    public function handle($command, callable $next)
    {
        if ($command instanceof QueuedCommand) {
            return $next($command->getCommand());
        }

        if ($command instanceof Message) {
            $this->producer->produce(new QueuedCommand($command));
            return;
        }

        return $next($comamnd);
    }
}