Using the 'after' parameter (timestamps) to loop through Reddit comments can miss some from busy threads

[sal-uva]

This can happen with super active threads where hundreds of comments are made per second (e.g. https://www.reddit.com/r/politics/comments/jo7lel/discussion_thread_2020_general_election_part_25/). Using "after_id" solves this.

[stijn-uva]

(after_id doesn't actually work in the current pushshift API)

[sal-uva]

This does work with the beta API, so let's hope the problem fixes itself.