close method
Implementation
Future<Map<String, dynamic>?> close() async {
////_log.finer("Closing cursor, cursorId = $cursorId");
state = State.closed;
if (cursorId != 0) {
var msg = MongoKillCursorsMessage(cursorId);
cursorId = 0;
db.executeMessage(msg, WriteConcern.unacknowledged);
}
return null;
}