setProperty method
Implementation
@mustCallSuper
void setProperty(String key, dynamic value) {
// Each key change will emit to `setStyle`
if (key == _STYLE_PROPERTY) {
assert(value is Map<String, dynamic>);
// @TODO: Consider `{ color: red }` to `{}`, need to remove invisible keys.
(value as Map<String, dynamic>).forEach(setStyle);
} else {
properties[key] = value;
}
}