Memory-wise, the cost is primarily the graphical memory buffer used for
rendering and is dependent on the screen size.

Latency-wise, the cost is primarily waiting for the OS callback to provide
Flutter with a rendering surface and compiling the remaining shader programs
that are not pre-emptively predictable. This is a one-time cost.

When the Flutter UI component is released, the UI-related memory is freed.
This doesn’t affect the Flutter state, which lives in the FlutterEngine
(unless the FlutterEngine is also released).

For performance details on creating more than one FlutterEngine,
see multiple Flutters.