ContentSizeCategory_Identifiable.swift

import SwiftUI

extension ContentSizeCategory: Identifiable {
    var id: Int { hashValue }
}

//Example
struct HelloWorld_Previews: PreviewProvider {
    static var previews: some View {
        Group {
            ForEach(ContentSizeCategory.allCases){ size in
                Text("Hello, World!")
                    .environment(\.sizeCategory, size)
            }
        }
        .previewLayout(PreviewLayout.sizeThatFits)
    }
}