Cursor as an index to start a query from.
The cursor index will be exclusive (i.e. the message at the cursor index will not be included in the result).
If undefined, the query will start from the beginning or end of the history, depending on the page direction.
Cursor as an index to start a query from. The cursor index will be exclusive (i.e. the message at the cursor index will not be included in the result). If undefined, the query will start from the beginning or end of the history, depending on the page direction.