Which events are accounted for in the Realtime report?
Explanation:
The Realtime Overview shows the top-ten pages on which users are active, the source for the users on each page, and the number of active users on each page. Active users are those who have sent a hit to Analytics within the last 30 minutes.
With the Realtime report, you can monitor activity as it happens. This report shows you events that took place within the last 30 minutes.
Read more here: https://support.google.com/analytics/answer/1638637