I have. In fact, some of my hand rolled stuff is actually _provably_ faster and more secure then even heavily battletested and widely used "industry standard" solutions. This is mainly due to them passing an exhaustive barrage of millions of lines of code of tests (literally, in fact I just did a pass over all my tests/ dirs and it's sitting at 6.3 million as of today) ranging from adversarial CVE probing attacks to fuzz tests. Ironically, my same testing suite has caught _numerous_ bugs in production stacks (openSSL/libuv) particularly, literal hard SIGSEGVs and the like.
On CVE probing, and I haven't really seen anyone describe/use it (or I may be oblivious), but the way you do it is you curate a list of CVEs for the class of software you're writing, say a web server. Then you take this list in chunks and hand them off to your agents to devise and implement adversarial technically analogous attacks against your codebase. If it's red, report and patch. Ironically (even with Fable 5) it's never complained/refused to do it.
On CVE probing, and I haven't really seen anyone describe/use it (or I may be oblivious), but the way you do it is you curate a list of CVEs for the class of software you're writing, say a web server. Then you take this list in chunks and hand them off to your agents to devise and implement adversarial technically analogous attacks against your codebase. If it's red, report and patch. Ironically (even with Fable 5) it's never complained/refused to do it.