If you want to see which one is faster (kind of pointless since both bun and deno/flash are not production ready) test your own application, and not an "hello world" or a specific workload that has been optimized to win a specific benchmark.
edit: as a silly point of reference, an hello world that writes the same headers and the same body on a 2016 intel macbookpro is able to serve 125k rps in bun, 145k rps in deno/flash and 140k rps in nodejs+uws.