Login to bot account.
Handle user command and reply it.
Since we can have many update type in updates. So we need to filter update events, like UpdateNewMessage, UpdateMessageSendSucceeded, UpdateMessageSendFailed, etc.
Send photo or album to chat.
When starting a bot, we may have some updates that are missed to process when a listener IS NOT ready.
So we need to keep specific update types in memory until a listener is set, then we can process those updates again.
Get update without event filter.