Unable to simulate the api_rate_limit in testing.

Unable to simulate the api_rate_limit in testing.
API Used - https://developer.box.com/guides/events/for-enterprise/ )
How to simulate rate_limit?
In the docs, it is mentioned that limit is 1000 call/minute. I hit with more than 1500 calls/minute. But I am unable to simulate the rate_limit.

https://developer.box.com/guides/api-calls/permissions-and-errors/rate-limits/#per-api-rate-limits