Callbacks from module - go

Question

I'm trying to learn go so I decided to make a go module. It works but now I want the main program to get notified when changes happen. In this example I just monitor when connected, but later on for many more changes in the device controlled.
The code below works but I can't see changes that happend in the module, for example the function "onHpd1Connected" in the main program is called when connected but shows that my connection is nil (even if I can see it is set in the "emit" function). The code must be compatible with multiple devices connected (hpd1, hpd2 etc..). I've tried pointers in different ways but without any luck. What I'm I doing wrong, and is this the best way to do it? Or would channels be a better option?
package main
import (
"fmt"
"sandbox/hyperdeck"
)
type hdc struct {
client hyperdeck.Hyperdeck
}
var hpd1 = hdc{
client: hyperdeck.NewHyperdeck("10.0.20.5", 9993),
}
func (hd hdc) onHpd1Connected() {
fmt.Println("Connected 1")
fmt.Println(hd)
}
func main() {
hpd1.client.On("connected", hpd1.onHpd1Connected)
hpd1.client.Connect()
}
and the module
package hyperdeck
import (
"errors"
"fmt"
"net"
"reflect"
"strconv"
"time"
)
const (
Open ConnectionState = 1
Connecting ConnectionState = 2
Closed ConnectionState = 3
)
type ConnectionState int
type HdCallback func()
type Hyperdeck struct {
Ip string
Port int
connection net.Conn
state ConnectionState
initialized bool
listeners map[string][]HdCallback
}
func (hd *Hyperdeck) connect() error {
if hd.state != Closed {
return errors.New("already connected to server: " + hd.Ip)
}
hd.initialized = false
hd.state = Connecting
var err error
hd.connection, err = net.DialTimeout("tcp", hd.Ip+":"+strconv.Itoa(hd.Port), time.Duration(time.Second*2))
if err != nil {
hd.state = Closed
return err
} else {
hd.state = Open
hd.emit("connected")
}
return nil
}
func (hd Hyperdeck) Connect() {
for {
if !hd.Connected() {
err := hd.connect()
if err != nil {
fmt.Println(err)
}
}
time.Sleep(time.Second * 1)
}
}
func (hd *Hyperdeck) Connected() bool {
return hd.state == Open && hd.connection != nil
}
func (hd Hyperdeck) emit(event string, params ...interface{}) {
fmt.Println(hd)
if listeners, exists := hd.listeners[event]; exists {
in := make([]reflect.Value, len(params))
for k, param := range params {
in[k] = reflect.ValueOf(param)
}
for _, cb := range listeners {
reflect.ValueOf(cb).Call(in)
}
}
}
func NewHyperdeck(ip string, port int) Hyperdeck {
hd := Hyperdeck{
Ip: ip,
Port: port,
initialized: false,
connection: nil,
listeners: map[string][]HdCallback{},
state: Closed,
}
return hd
}
func (hd Hyperdeck) On(event string, callback func()) {
if _, exists := hd.listeners[event]; !exists {
hd.listeners[event] = make([]HdCallback, 0)
}
hd.listeners[event] = append(hd.listeners[event], callback)
}