public function start($key)
    {
        $key = strtolower($key);

        $this->benchmarks[$key] = [
            'start_time'    => microtime(true),
            'stop_time'     => 0.0,
            'avg_time'      => 0.0,
            'start_memory'  => memory_get_usage(true),
            'stop_memory'   => 0,
            'avg_memory'    => 0,
            'peak_memory'   => 0,
            'running'       => true
        ];
    }