addError method Null safety
Sends or enqueues an error event.
null, it is replaced by a NullThrownError.
Listeners receive this event at a later microtask. This behavior can be
overridden by using
sync controllers. Note, however, that sync
controllers have to satisfy the preconditions mentioned in the
documentation of the constructors.
void addError(Object error, [StackTrace? stackTrace]);