Count the number of events that are accumulated and being sent
Add two types of counter.
- Count the number of events we are accumulating
- Count the number of events we are sending
This is to keep track of the number of events and ensure we handle them efficiently.
Relates to: https://gitlab.com/gitlab-com/dev-sub-department/section-dev-request-for-help/-/issues/199#note_1739522657.