lazyみながら読んでたWriteImplKindにsetterとは別でmodifierの定義あったわ

enum class WriteImplKind { /// It's immutable. Immutable, /// There's storage. Stored, /// There are observers on top of the storage. /// TODO: maybe add a StoredWithDidSet here and to ReadWriteImplKind? StoredWithObservers, /// There are observers on top of the superclass's write implementation. InheritedWithObservers, /// There's a setter. Set, /// There's a mutable addressor. MutableAddress, /// There's a modify coroutine. Modify, };