>http://en.wikipedia.org/wiki/Real-time_operating_system

Specifically:

A hard real-time operating system has less jitter than a soft real-time operating system. The chief design goal is not high throughput, but rather a guarantee of a soft or hard performance category. A RTOS that can usually or generally meet a deadline is a soft real-time OS, but if it can meet a deadline deterministically it is a hard real-time OS.

Async, non-blocking, and event-driven have nothing to do with real-time.

This web framework has nothing to do with real-time.

Stop using terminology you don't understand.