Client ID appears in Get presence twice, like two clients with the same ID are present.

[Rosalita]

Please note this issue appears in ably-go 1.2.6 however it doesn't reproduce in 1.2.5

When a Realtime client enters their presence to a brand new channel and there is a short delay before they get channel presence, their client's ID is returned twice.

I've been able to recreate this issue with the following script.

package main

import (
	"context"
	"fmt"
	"os"
	"bytes"
	"time"
	"github.com/ably/ably-go/ably"
)


func main() {
	ctx := context.Background()

	key, _ := os.LookupEnv("ABLY_PRIVATE_KEY")

	client, err := ably.NewRealtime(
		ably.WithKey(key),
		ably.WithClientID("Client A"),
	)
	if err != nil {
		fmt.Println(err)
		return
	}

	// To recreate the bug set channel name to a new name each time this script is run
	// this results in the Get creating a brand new channel rather than fetching an existing channel
	myChannel := client.Channels.Get("channel1")
	myChannel.Presence.Enter(ctx, nil)

	// This bug occurs when there is a delay after entering presence
	time.Sleep(time.Second * 5)

	presenceMessages, err := myChannel.Presence.Get(ctx)
	if err != nil {
		fmt.Println(err)
		return
	}

	var buffer bytes.Buffer

	for i, msg := range presenceMessages {
		if msg != nil {
			buffer.WriteString(msg.ClientID)
			// if not the last message, add a comma and a space.
			if i != len(presenceMessages)-1 {
				buffer.WriteString(", ")
			}
		}
	}
	
	fmt.Println(buffer.String())
	// When the bug happens in ably-go 1.2.6 "Client A, Client A" is printed
	// in ably-go 1.2.5 this script prints "Client A"

}

┆Issue is synchronized with this Jira Task by Unito