use quic example code to connect to mq over tcp fail

[gavinshao111]

Describe the bug
In quic demo, connect mq over tcp fail.

Expected behavior
Connect successful.

Actual Behavior
Connect fail.

To Reproduce

** Environment Details **

• NanoSDK/NNG version
• Operating system and version
• Compiler and language used
• Shared or static library
• Remote MQTT Broker info
  mqx config:
  listeners.tcp.default {
  bind = "0.0.0.0:1883"
  max_connections = 1024000
  }
  listeners.quic.default {
  enabled = true
  bind = "0.0.0.0:14567"
  max_connections = 1024000
  }
• Messaging scenario

Additional context
connect mqtt-tcp://10.192.8.158:1883 fail, but connect to mqtt-tcp://10.192.8.158:14567 successful, console output:

[panzhao@localhost quic]$ ./quic_client conn mqtt-tcp://10.192.8.158:1883
QUIC Stream closed, pipe finit!
[Disconnected][CLIENT FOR QUIC]...
^C
[panzhao@localhost quic]$ ./quic_client conn mqtt-tcp://10.192.8.158:14567
[Msg Sent][CLIENT FOR QUIC]...
[Connected][CLIENT FOR QUIC]...
^C
[panzhao@localhost quic]$ ./quic_client conn mqtt-quic://10.192.8.158:14567
[Msg Sent][CLIENT FOR QUIC]...
[Connected][CLIENT FOR QUIC]...

[JaylinYu]

Seems like it still goes into QUIC transport layer. Need your client code to proceed

[wanghaEMQ]

Thanks for your issue.

In quic client. It seems that we do not check the scheme(mqtt-tcp or mqtt-quic) before it goes to quic transport layer. So you can connect to mqtt broker over quic (on 14567 port).

But quic client is NOT supported to connect to mqtt broker over tcp (on 1883 port) if you don't modify the codes therein.

We will fix the scheme check problem at later. And if you want to connect mqtt broker over tcp. You could use mqtt or mqtt_async example.

[JaylinYu]

nng_mqtt_quic_client_open doesn't check scheme now