Benchmark.js fixed overhead for setup functions

[OliverNChalk]

Any function passed into new Benchmark(options.setup) will result in a considerable drop in tested function performance. It appears to be a fixed overhead unrelated to what is actually done in the setup function. Here are typescript and javascript examples reproducing the problem.

4423.295430464231 ops/s Custom Test Runner
4815.623863547339 ops/s NoSetup (benchmark.js)
4267.906011630515 ops/s DeclaredSetup (benchmark.js)
4278.495863955272 ops/s AssignedSetup (benchmark.js)

[Uzlopak]

I will have a look at it.