Count number of iterations.

dart/site/try/poi/repeat_poi.dart

Index: dart/site/try/poi/repeat_poi.dart
diff --git a/dart/site/try/poi/repeat_poi.dart b/dart/site/try/poi/repeat_poi.dart
index 24e837af5d474d752574522b132fe052b2665dbc..32a704fc1ae6b29bc9cd0a5fd58a3bf217718209 100644
--- a/dart/site/try/poi/repeat_poi.dart
+++ b/dart/site/try/poi/repeat_poi.dart
@@ -4,6 +4,14 @@
 
 import 'poi.dart' as poi;
 
+int count = 0;
+
+int MAX_ITERATIONS =
+    const int.fromEnvironment('MAX_ITERATIONS', defaultValue: null);
+
 main(arguments) {
+  count++;
+  if (MAX_ITERATIONS != null && count > MAX_ITERATIONS) return;
+  print('\n\n\n\nIteration #$count.');
   poi.main(arguments).then((_) => main(arguments));
 }