Unsubscribe get stuck

[dborovcanin]

Unsubscribe token.Wait() waits indefinitely, even if Unsubscribe Ack is received. This was not happening before PR 361. Looks like the problem is related to the code removed from net.go. You can use the following snippet to get stuck:

	mc := mqtt.NewClient(opts)
	token := mc.Connect()
	token.Wait()
	if err := token.Error(); err != nil {
		fmt.Printf(err)
		return
	}
	mc.Subscribe(topic, 2, handler)
	// Wait for SUB ACK.
	time.Sleep(3 * time.Second)
	if mc.Unsubscribe(topic).Wait() {
		fmt.Println("done")
	}
        // Never reached. Network inspection shows Unsubscribe ACK received.
	fmt.Println("never reached")

[alsm]

Thanks for reporting this, I didn't notice that the changes that were made for subscribe hadn't been made for unsubscribe and it didn't break the tests (unfortunately)

[robbawebba]

@dusanb94 I apologize for breaking the behavior of your application (and probably others), and thank you @alsm for fixing the issue! I totally forgot about the unsubscribe flow because my application does not use the unsubscribe features of this client, and I just relied on the library's test suite for verifying that I did not break any existing functionality.