Configurable offset cutoff with CursorPagination

[rowanseymour]

Picking up where the #3143 ended.. in our API implementation we generally order by a combination of a millisecond accuracy timestamp and pk, e.g.

class ModifiedOnCursorPagination(CursorPagination):
    ordering = ('-modified_on', '-pk')

It's possible sometimes for large numbers of items to end up with the same timestamp so we've been overriding decode_cursor so that we can increase OFFSET_CUTOFF (malicious queries are less of a concern in this case). Seems like that value could be configurable though, so happy to make a simple PR if there's a consensus on whether it should be a class variable or settings value.

[lovelydinosaur]

Seems like that value could be configurable though

I'd suggest subclassing, setting offset_cutoff, and then adding that new class as the default pagination class in the settings.

[rowanseymour]

Not a great solution for us because then we have to replicate the code in CursorPagination.decode_cursor in our subclass

[lovelydinosaur]

I'd have no problem with a PR that simply moved the OFFSET_CUTOFF to a class attribute .offset_cutoff. Ignore the test case in #3143 and that'd be fine as a two-liner change.