Fix rolling averages in diagnostic status.

pkg/analysis_server/lib/src/domain_diagnostic.dart

Index: pkg/analysis_server/lib/src/domain_diagnostic.dart
diff --git a/pkg/analysis_server/lib/src/domain_diagnostic.dart b/pkg/analysis_server/lib/src/domain_diagnostic.dart
index 22e34880dc0c92803c6228741e6d54a44e4c80a6..5d30d928522894ed4439f9b45913490fbdc19b22 100644
--- a/pkg/analysis_server/lib/src/domain_diagnostic.dart
+++ b/pkg/analysis_server/lib/src/domain_diagnostic.dart
@@ -138,7 +138,7 @@ class Sampler {
   }
 
   /// Get the average for the context associated with the given [folder].
-  int getAverage(Folder folder) {
+  num getAverage(Folder folder) {
     resetTimerCountdown();
     return averages[folder].value;
   }