debugAssertIsValid method
override
In debug mode, throws an exception if the object is not in a valid configuration. Otherwise, returns true.
This is intended to be used as follows:
assert(myWidgetSpan.debugAssertIsValid());
Implementation
@override
bool debugAssertIsValid() {
// WidgetSpans are always valid as asserts prevent invalid WidgetSpans
// from being constructed.
return true;
}