added new DiscoveryHeartbeatEvent

src/main/java/org/springframework/cloud/client/discovery/DiscoveryHeartbeatEvent.java

@@ -0,0 +1,20 @@
+package org.springframework.cloud.client.discovery;
+
+import org.springframework.context.ApplicationEvent;
+
+/**
+ * @author Spencer Gibb
+ */
+public class DiscoveryHeartbeatEvent extends ApplicationEvent {
+
+	private final Object value;
+
+	public DiscoveryHeartbeatEvent(Object source, Object value) {
+		super(source);
+		this.value = value;
+	}
+
+	public Object getValue() {
+		return value;
+	}
+}