Github user zentol commented on a diff in the pull request:
https://github.com/apache/flink/pull/4826#discussion_r145114119
--- Diff:
flink-streaming-java/src/main/java/org/apache/flink/streaming/util/latency/LatencyHistogramStatistics.java
---
@@ -0,0 +1,71 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.flink.streaming.util.latency;
+
+import org.apache.flink.metrics.HistogramStatistics;
+
+import org.apache.commons.math3.stat.descriptive.DescriptiveStatistics;
+
+
+/**
+ * Latency histogram statistics implementation returned by {@link
LatencyHistogram}.
+ * The statistics class wraps a {@link DescriptiveStatistics} instance and
forwards the method calls accordingly.
+ */
+public class LatencyHistogramStatistics extends HistogramStatistics {
--- End diff --
same principle as the latencyHistogram.
---
