Am I misunderstanding this or is this an article about how Chars[].resize works in a library they wrote by themselves ? Or is it a misunderstanding of how resiz

Am I misunderstanding this or is this an article about how Chars[].resize works in a library they wrote by themselves ? Or is it a misunderstanding of how resize works in general ? I am not trying to take anything away from the author but digging into assembly instead of simply looking up the docs seems like a long road to go for calling it an optimization. Another thing is that why does this even exist ? The tests are showing some sql executions but is that real production executions or simply to test a possible optimization in a different context. I am not mentioning in as a premature optimization because I am not sure whether I am bright enough to tell what is going on. Please clarify