Issue Description:

We had an active effort a few years ago to look into eager bridging for the hashed collections. That effort has unfortunately fizzled out due to age and neglect, but there are parts of it that may be salvageable in the current iteration of the standard library. An old reference implementation can be found at #5703 but that is now bitrotted. The general approach is still worthwhile, though, and we should try to update it and benchmark it again.

Who knows, there might finally be some real wins.