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(myInlineSpan.debugAssertIsValid());
Implementation
@override
bool debugAssertIsValid() {
assert(false, 'Consider implementing the WidgetSpan interface instead.');
return super.debugAssertIsValid();
}