Since we are supporting all functions of coap , we should have test case for all methods with all options with some publicly available coap sever like https://coap.me/crawl/coap://coap.me

Suggestion for KeepClient Connection Alive https://github.com/1998-felix/coap-cli/blob/d4705eed8646741d28d1fd7a2aac0bc9bb987368/coap/client.go#L29-L36

func New(addr string) (Client, error) {
	c, err := udp.Dial(addr, options.WithKeepAlive(10, 60*time.Second, func(cc *client.Conn) { fmt.Println(cc.Ping(cc.Context())) }))
	if err != nil {
		log.Fatalf("Error dialing: %v", err)
	}

	return Client{conn: c}, nil
}

In additonal , It will be great if we provide flags to set have keep Alive time out in client

If flag is not available defaults to 60 seconds.

If KeepAlive Time flag is 0 then it should not add KeepAlive function during connect.

Server disconnection idle client leads to new problem
The client doesn't know the disconnection, and client again send disconnection request to server
So we are getting error in server like {"time":"2024-05-16T10:17:46.594334142Z","level":"WARN","msg":"Unsubscribe failed to complete successfully","duration":"31.172803ms","channel_id":"dff59205-90d6-430d-9903-a611cd401bb3","error":"not subscribed"}