Parsing 1 Billion Rows in Bun/Typescript Under 10 Seconds

Bun tries to swallow files over 4GB and promptly chokes. The culprit? Its Buffer caps out at 4GB. The fix? Slice files into chunks under 4GB but keep the buffer lean, no more than 128KB, to keep things zippy. Pull out the big guns—workers. This move fires up all CPU cores, slashing processing time from 18.65s to 9.22s. And yep, go manual with UTF-8 parsing. It's Bun's single-threaded quirk, and it's kind of charming.