Container Controller Holder
Returns the ViewDataBinding containing the PanelContainerView, if any. It is used to optimise the initialization of the PanelContainerController. This function is only called when panelContainerViewContext is set for the first time.
If findContainerViewDataBinding returns a valid ViewDataBinding then the holder listens for binding updates and invokes createPanelContainerController on update completing. That guarantees that a controller is created once when all property updates are completed.
Called when the holder has sufficient information for creating a PanelContainerController. The returned controller will be bound to the system UI and unbound when the controller is cleared or replaced. The function may return
null when it is not ready to create a controller. In these cases it's common for the information that the controller creation depends on to be set using a delegate returned by rebuildOnChange such that controller creation is automatically re-attempted when then information becomes available.
Creates a delegate that recreates the controller when the value delegate's value changes. This is intended to be used for information that the controller depends on and cannot be changed within the controller itself.