Benchmark code to go with the blog post on the same topic.
https://www.marginalia.nu/log/a_110_java_io/
Some of the code is not identical to the code in the blog post, but homomorphic and the results are the same.
The number of iterations is by default dialed down to 10,000,000 from 100,000,000 to make the benchmark run faster when developing new benchmarks, with the results scaled up proportionately.
The code assumes Java 22.