removeValue method
Removes the key from the registry.
If, and only if, the key was registered on the registry will this fire
an event on the valueStream with the key so listeners can be notified
that the value has changed.
This accepts an optional originator to allow widgets that remove values
to know when the stream fires if they are responding to their own event or
not.
Implementation
dynamic removeValue(
String key, {
String? originator,
}) {
assert(key.isNotEmpty == true);
var hasKey = _values.containsKey(key);
var result = _values.remove(key);
if (hasKey == true) {
_valueStreamController?.add(WidgetValueChanged(
id: key,
originator: originator,
value: null,
));
}
return result;
}