This adds the ability for bundles to be turned into a "Toolbag" that functions like a hotbar swapper.

Simply craft a bundle (the default recipe is added in this datapack) and name it Toolbag.
Then when it is in your offhand you can shift and store your current hotbar inside the Toolbag.
Toss the items at your feet to return the stored hotbar and the items will return in the correct order. If you toss the items away from you the order gets messed up unless you can get there before the pickup delay timer ends.

Also, I recommend removing the Toolbag from your offhand when not switching so you don't accidentally chuck your amazing tools into lava or something.