This method indicates whether or not the runtime will regard the method as virtual (as indicated by the presence of the "virtual" modifier in the signature). WARN WARN WARN: We won't have a final value for this until declaration diagnostics have been computed for all symbols, so pass ignoringInterfaceImplementationChanges: true if you need a value sooner and aren't concerned about tweaks made to satisfy interface implementation requirements. NOTE: Not ignoring changes can only result in a value that is more true.