How can a bot send a message to the user, when user just opens the chat.
Example:
- User has already added a
Telegram bot
to his list of contacts and started conversation - Later on, user opens the chat window with that bot
- Bot "sees" that user has opened the chat window, but hasn't written anything yet
- Bot should say "hello, what can I help you with?" to the user
Is there any event/trigger for a step #3 in Telegram Bot API?