cancel_subscriptions

Uncancelled instance of 'StreamSubscription'.

The analyzer produces this diagnostic when an instance of StreamSubscription is created but the method cancel isn't invoked.

The following code produces this diagnostic because the subscription isn't canceled:

import 'dart:async';

void f(Stream stream) {
  // ignore: unused_local_variable
  var subscription = stream.listen((_) {});
}

Cancel the subscription:

import 'dart:async';

void f(Stream stream) {
  var subscription = stream.listen((_) {});
  subscription.cancel();
}