Marks the attached component of type T as changed, so that its
[OnComponentChanged] handler runs once during the next update.
Call this method after you change component data directly, for example by writing through
ref GetComponent<T>(). Unity doesn't detect direct writes, so without this call
the handler doesn't run. You don't need to call this method when you use the generated
SetXxx setters or a data binding; both call it for you. If no component of type
T is attached to this element, this method does nothing.