Struct initializer in extension

Using Swift
4

I can't define it in the struct itself because that's in a separate package I don't own. I tried to call the auto-generated initializer (it's the first thing I tried), but got:

let pm = PageMetadata(page: 1, per: 1, total: 1)
                     --
Extra arguments at positions #1, #2, #3 in call
Missing argument for parameter 'from' in call