Vertical Toolbars & Tab Bars on iPhone Duo

import SwiftUI

struct InboxView: View {
    @Environment(\.toolbarVerticalEdge) private var toolbarVerticalEdge

    var body: some View {
        NavigationStack {
            MessageList()
                .toolbar {
                    ToolbarItem(placement: .primaryAction) {
                        Button("Compose", systemImage: "square.and.pencil") { }
                            .visibilityPriority(.high)
                    }
                    ToolbarItem(placement: .bottomBar) {
                        Button("Archive", systemImage: "archivebox") { }
                            .visibilityPriority(.standard)
                    }
                    ToolbarItem(placement: .bottomBar) {
                        Button("Flag", systemImage: "flag") { }
                            .visibilityPriority(.low)
                    }
                }
                .toolbarVerticalCompressionBehavior(.prefersToolbarItems)
        }
    }
}

struct MessageList: View {
    var body: some View { Text("Messages") }
}