def count_unseen(self):
        if self.track_unseen:
            return self.feed_markers.count('unseen')
Get the events that occurred between the *start* and *end* POSIX timestamps,
dataset/ETHPy150Open tschellenbach/Stream-Framework/stream_framework/feeds/notification_feed/base.py/BaseNotificationFeed.count_unseen--crossover with--dataset/ETHPy150Open DataDog/dogapi/src/dogapi/http/events.py/EventApi.stream