The problem is that existing connections are inside of async functions (goroutines) that have references to the old config. AFAIK, there's no way in Go's stdlib

The problem is that existing connections are inside of async functions (goroutines) that have references to the old config. AFAIK, there's no way in Go's stdlib to kill those goroutines while keeping the connection and handing it to another fresh goroutine. To be clear, the new config is running at the same time as the old is still tearing down; all new connections get handled by the new config. Listeners are shared and transferred between servers. We're all ears, though, if someone with deep knowledge of Go's internals can point us in the right direction.