I guess you shuffled this all around because it got faster this way - I don't see a reason otherwise.
So here's my 2 cents:
Maybe the alignment could *still* be improved by moving `fieldType` below `flags`.
Maybe even with `_ byte` (or `_ [5]byte`) to keep it divisible by 4 resp. 8 before `name`.
Maybe even by making `fieldType` and `flags` an `int`...?