subscription method
Execute a Subscription from a Document
Implementation
Future<Snapshot> subscription(
String document, {
String? key,
Map<String, dynamic>? variables,
Map<String, String>? headers,
}) async {
final _document = document.trim();
final _key = key ?? _keyGenerator.generateBase(document);
return executeSubscription(
Query(
key: _key,
headers: headers,
document: _document,
variables: variables,
),
);
}