prepareInitialFrame method Null safety

void prepareInitialFrame()

Bootstrap the rendering pipeline by preparing the first frame.

This should only be called once, and must be called before changing configuration. It is typically called immediately after calling the constructor.

This does not actually schedule the first frame. Call PipelineOwner.requestVisualUpdate on owner to do that.


void prepareInitialFrame() {
  assert(owner != null);
  assert(_rootTransform == null);
  assert(_rootTransform != null);