Github user achristianson commented on a diff in the pull request:
https://github.com/apache/nifi-minifi-cpp/pull/134#discussion_r137585243
--- Diff: libminifi/include/core/state/metrics/MetricsListener.h ---
@@ -0,0 +1,131 @@
+/**
+ *
+ * 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.
+ */
+#ifndef LIBMINIFI_INCLUDE_C2_METRICS_H_
+#define LIBMINIFI_INCLUDE_C2_METRICS_H_
+
+#include <vector>
+
+#include "MetricsBase.h"
+#include "core/state/UpdateController.h"
+
+namespace org {
+namespace apache {
+namespace nifi {
+namespace minifi {
+namespace state {
+namespace metrics {
+
+/**
+ * Purpose: Class that will represent the
--- End diff --
Incompete comment
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