nextCursor

Cursor for the next page when this state belongs to a grouped query. null means there is no further page (or that this is a standard query that doesn't use cursors).

After a reconnect, the first page is refreshed, and the pages loaded before can be kept when the sync covered their channels. The cursor then follows the refreshed first page, so the next pages can hold channels that are already loaded. Keep loading until a page brings channels that are not loaded yet, or the cursor is null.