SwipeViewAlignmentEdge contentSize Problem

[WenchaoD]

Hi there. There is a contentsize problem when I set the alighment to SwipeViewAlignmentEdge. I set this property for keeping a short horizontal spacing between items. I have 8 items, but the content size is larger than 8, maybe 9. I checked this code:

When I changed it to:

It would works fine. I want to know if you calculate in that way on purpose so that I can determine whether to submit a PR. And why if you do.