Create a route to match the port on which the call was received.
The selector checks the io.ktor.request.ApplicationRequest.local request port, ignoring HTTP headers such as “Host” or “X-Forwarded-Host”. This is useful for securing routes under separate ports.
For multi-tenant applications, you may want to use io.ktor.routing.port, which takes HTTP headers into consideration.
port - the port to match against
IllegalArgumentException - if the port is outside the range of TCP/UDP ports