Benchmark against `btoa` and `atob`?

[mristin]

Hi, Thanks a lot for your work on this library! I'm curious if you perhaps benchmarked your solution against browser built-in functions btoa and atob?

If not, I could volunteer to set up a benchmark and create a PR to include the results in the readme if that's desirable? Do you have any preferance on how to benchmark?

[mholt]

I found this one: https://jsben.ch/p3Cbs