Configuring a Sliding Window for 5 requests per second

I have a Job that makes a single request to a webserver, and that webserver only allows 5 requests per second. This has lead me to the following SlidingWindowOptions:

new SlidingWindowOptions(limit: 5, interval: TimeSpan.FromSeconds(1), buckets: 1)

But as your documentation states, a Sliding Window with 1 bucket is the same as a Fixed Window, and I run into the issue described: it will sometimes make 5 requests at the end of one second and 5 at the start of the next, which will fail because this is basically 10 in a second.

The behavior I want, is that for any given second, no more than 5 requests are made. I find the documentation around buckets very hard to understand, so how do I configure it correctly?