How to write an atomic property wrapper for static variable?

[jamieQ (Jamie)]

@Danny

import typealias Synchronization.Mutex

@propertyWrapper struct Storage<Element: Hashable & Sendable>: Sendable, ~Copyable {
  typealias WrappedValue = Set<Element>
  private let _wrappedValue: Mutex<WrappedValue>

  init(wrappedValue: WrappedValue) { _wrappedValue = .init(wrappedValue) }

  var wrappedValue: WrappedValue {
    get { _wrappedValue.withLock(\.self) }
    nonmutating set { _wrappedValue.withLock { $0.formUnion(newValue) } }
  }
}

tangential to the core discussion here, but since this came up recently, using a struct property wrapper to wrap values in a mutex probably does not do what one generally wants it to.