+// Determine listenURL (addr:port where server should bind) and
+// internalURL (target url that client should connect to) for a
+// service.
+//
+// If the config does not specify ListenURL, we check all of the
+// configured InternalURLs. If there is exactly one that matches our
+// hostname, or exactly one that matches a local interface address,
+// then we use that as listenURL.
+//
+// Note that listenURL and internalURL may use different protocols
+// (e.g., listenURL is http, but the service sits behind a proxy, so
+// clients connect using https).