We should identify the right balance point between loading the embedding / vm / isolate / framework / userland element tree / resources in the tree based on each part’s load time vs its memory use.

This involves #32945 to audit cold init time and also auditing memory consumption.

Our recommended embedding strategy + default behaviors from APIs should be reasonably balanced between fast loading and memory usage.

Document alterations users can make given those APIs such as prewarming/keeping the vm only, prewarming/keeping the isolate. Flutter side APIs to flush parts of the tree when window is not visible.