Writing a simple Django middleware that times requests

# ======================================================================
# Q: Write a simple Django middleware.
# ======================================================================

class RequestTimingMiddleware:
    def __init__(self, get_response):
        self.get_response = get_response
    def __call__(self, request):
        start = time.perf_counter()
        response = self.get_response(request)
        response['X-Response-Time'] = f'{(time.perf_counter()-start)*1000:.1f}ms'
        return response