feat: add feature to provide external counters

Author: mhabedinpour

client.go

@@ -34,6 +34,17 @@ func (i *IPMux) Client() *http.Client {
 	return i.clients[i.counter.Load()%length]
 }
 
+// ClientWithCounter returns one of the clients that is associated with one of the IPs given in New.
+// the function is safe to use without error handling of the constructor. it returns http.DefaultClient when there are no available clients.
+func (i *IPMux) ClientWithCounter(counter uint64) *http.Client {
+	length := uint64(len(i.clients))
+	if length == 0 {
+		return http.DefaultClient
+	}
+
+	return i.clients[counter%length]
+}
+
 // Clients returns a list of all clients created for the list of ips given in New.
 // the function is safe to use without error handling of the constructor. it returns a list containing ob client (http.DefaultClient) when there are no available clients.
 func (i *IPMux) Clients() []*http.Client {