createNativePlatformViewId

Returns a fresh, unique id for one native/embedded view of this flow.

Call it once per view instance and keep the result for that view's lifetime: the id keys both the per-view events observer and the native view manager, so two views sharing an id would overwrite each other's observer and misroute events. Deriving it from instanceIdentity alone is not enough — the same flow can be embedded more than once.