bindings property
Where each property's value comes from, when it is not a literal: property key → SceneBinding.
The READ plane's provenance, and empty in a compiled scene — there a
property that reads a parameter reads a Dart variable, and nothing has
to be recorded about it. The property here still holds the resolved
value, and the binding is the stronger of the two: an edit to a bound
property is written to what it is bound to
(reconcileBindings), so a save always spells the reference and never
silently bakes a value in. See read_plane.dart.
Implementation
final bindings = <String, SceneBinding>{};