anchor.diff:    test("events prevent timeout", () {
       Stopwatch sw = new Stopwatch();
       StreamController c = new StreamController();
  -    Stream tos = c.stream.timeout(halfSec, onTimeout: (_) {
  +    Stream tos = c.stream.timeout(twoSecs, onTimeout: (_) {
         int elapsed = sw.elapsedMilliseconds;
         if (elapsed > 250) {
           // This should not happen, but it does occasionally.
  
positive.code:       }
        fail("Timeout not prevented by errors");
      });
      tos.listen((_) {},
        onError: (e, s) {
          expect(e, "ERROR");
        },
        onDone: expectAsync0((){}));
      int ctr = 200;  // send this many error events at 5ms intervals. Then close.
      new Timer.periodic(ms5, (timer) {
        sw.reset();
  
negative.code:       }
      });
      sw.start();
  
      tos.listen((v) { expect(v, 42);}, onDone: expectAsync0((){}));
    });
  
    test("errors prevent timeout", () {
      Stopwatch sw = new Stopwatch();
      StreamController c = new StreamController();
      Stream tos = c.stream.timeout(twoSecs, onTimeout: (_) {
        int elapsed = sw.elapsedMilliseconds;
        if (elapsed > 250) {
          // This should not happen, but it does occasionally.
  