https://developer.apple.com/documentation/SwiftUI/View/toolbarMinimizeBehavior(_:for:)
Use this modifier to enable toolbar minimization in response to scrolling. The supported placement is navigationBar. When the navigation bar minimizes, an integrated top tab bar will also minimize.
By default, the safe area adjusts as the navigation bar minimizes. Use toolbarMinimizationSafeAreaAdjustment(_:for:) to customize this.
https://developer.apple.com/documentation/SwiftUI/View/toolbarMinimizeBehavior(_:for:)