Passing large amounts of data between actors without making copies

Using Swift
12

Could you please clarify?

The usage of that class (in the provided example) is basically:

    product.name = generateRandomString(length: 5)

which I changed to:

            product.withLock { product in
                product.name = generateRandomString(length: 5)
            }

And this is the sensibility change I did:

Originally was:

nonisolated final class WorkProduct {
    var id = UUID()
    var name : String? = nil
    var data = Data(repeating: 0xFF, count: 1024)
}

Changed to be Sendable:

nonisolated final class WorkProduct: @unchecked Sendable {
    struct State {
        var id = UUID()
        var name : String? = nil
        var data = Data(repeating: 0xFF, count: 1024)
    }
    private var state = State()
    private var lock = NSLock()
    
    func withLock<R>(_ body: (inout State) -> R) -> R {
        lock.withLock {
            body(&state)
        }
    }
}

What could go wrong with this change?

Or does this qualify as a redesign now that the class API is slightly different?