TBH it sounds like it would be extremely against the whole "simplicity, even at high costs" philosophy the Golang people strive for. Deploying new handlers into a running web service seems much more like something the Erlang people would be interested in.

(and lo, the BEAM does indeed allow hot code reloads. I don't think this is commonly used in BEAM-based Erlang/Elixir web services though. Certainly the Gleam people don't seem to like hot reloads very much...)