startAt method
Create a query constrained to only return child nodes with a value greater than or equal to the given value, using the given orderBy directive or priority as default, and optionally only child nodes with a key greater than or equal to the given key.
Implementation
Query startAt(Object? value, {String? key}) {
return Query._(
_queryDelegate,
_modifiers.start(StartCursorModifier.startAt(value, key)),
);
}