Get information about annotation
getCallbackAnnotation is intended to be invoked by annotation callback functions. If it is invoked from an annotation callback function, it returns an instance of Simulink.Annotation class that represents the annotation associated with the callback function. The callback function can then use the instance to get and set the annotation's properties, such as its text, font and color. If this function is not invoked from an annotation callback function, it returns nothing, i.e., .