Made dashboard data emission interval configurable on startup

hystrix-data-stream/src/main/java/com/netflix/hystrix/metric/consumer/HystrixDashboardStream.java

@@ -15,6 +15,8 @@
  */
 package com.netflix.hystrix.metric.consumer;
 
+import com.netflix.config.DynamicIntProperty;
+import com.netflix.config.DynamicPropertyFactory;
 import com.netflix.hystrix.HystrixCollapserMetrics;
 import com.netflix.hystrix.HystrixCommandMetrics;
 import com.netflix.hystrix.HystrixThreadPoolMetrics;
@@ -31,6 +33,9 @@ public class HystrixDashboardStream {
     final Observable<DashboardData> singleSource;
     final AtomicBoolean isSourceCurrentlySubscribed = new AtomicBoolean(false);
 
+    private static final DynamicIntProperty dataEmissionIntervalInMs =
+            DynamicPropertyFactory.getInstance().getIntProperty("hystrix.stream.dashboard.intervalInMilliseconds", 500);
+
     private HystrixDashboardStream(int delayInMs) {
         this.delayInMs = delayInMs;
         this.singleSource = Observable.interval(delayInMs, TimeUnit.MILLISECONDS)
@@ -60,7 +65,9 @@ public void call() {
                 .onBackpressureDrop();
     }
 
-    private static final HystrixDashboardStream INSTANCE = new HystrixDashboardStream(500);
+    //The data emission interval is looked up on startup only
+    private static final HystrixDashboardStream INSTANCE =
+            new HystrixDashboardStream(dataEmissionIntervalInMs.get());
 
     public static HystrixDashboardStream getInstance() {
         return INSTANCE;