how to send a message to the specified topic of a supergroup?

[ip75]

I have

• group_id (chat_id, supergroup)
• and I have message_thread_id of every topic.

How can I send a message to a specified topic of a supergroup? This recipient selects only General topic of the group.

sender := message.NewSender(client.API())
r := sender.To(&tg.InputPeerChannel{
ChannelID:  mtprotoGroupID,
AccessHash: AccessHash,
})

[ip75]

to send a message to the specific topic.

1. read about how to send to topics in
   https://core.telegram.org/api/forum#forum-topics
   to realize

2. _, err := r.Reply(topicID).Text(ctx, "msg to topic")