Background

Design: https://flutter.dev/go/multi-view-sync-over-async

Adding/removing a view from the engine is an asynchronous operation. However, desktop embedders expose a synchronous API. Today, desktop embedders block the platform thread until the engine completes the add/remove operation.

Blocking the platform thread like this is unnecessary if the platform thread doesn't use the view immediately.

Solution

Use lazy blocking: only block the platform thread if it attempts to do something that is affected by a pending view add/remove operation.