I test load with various tools, but most will just send many requests all at once without much control over the rate at which the hits are being sent.

Today I was reading a web post about nginx mirroring and the author mentioned a tool named "hey". It is actually written in Go and can be found here:

https://github.com/rakyll/hey

This tool has options such as the -q to limit the number of requests per second. The -c is also important, it offers a way to define the number of concurrent requests. You can also use the -t option to define a timeout other than the default of 20 seconds to see how long it takes requests to come out positively.