Type of action to broadcast. Choose one, depending on what the user is about to receive: typing for text messages, upload_photo for photos, record_video or upload_video for videos, record_audio or upload_audio for audio files, upload_document for general files, find_location for location data, record_video_note or upload_video_note for video notes.

identifier for the target chat or username of the target channel (in the format @channelusername).