If it's the holy grail, then erlang has had it for a couple decades... and whether it actually works in nginx I don't know, but it does work in erlang.
The way it's handled is that the process where the previous socket was connected remains in place until it terminates but all new sockets connect to the new code.
The way it's handled is that the process where the previous socket was connected remains in place until it terminates but all new sockets connect to the new code.