Slightly confused - why do you remove the first item here?

For services and configuration values you get back `next_marker` attribute which points to a first item on the next page. In this case you don't need to remove a first item, because it's unique.

It's true though that events feed API works a bit differently. In the events feed API you use the last item id as a marker which means you do get the same last item back on a subsequent request with `?marker` provider. In this case you do need to remove the first returned item if you don't want to have a duplicated item.

For example of the second approach (events feed) you can look at the EventsFeedPoller class in the Node.js client.