Eradicate all uses of std::bind()

Change-Id: I6e1ccf2d87b76142e6d519c1a288d03022e4d167
diff --git a/tools/ping/server/tracer.hpp b/tools/ping/server/tracer.hpp
index b8b6952..a84b72e 100644
--- a/tools/ping/server/tracer.hpp
+++ b/tools/ping/server/tracer.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2015,  Arizona Board of Regents.
+/*
+ * Copyright (c) 2015-2021,  Arizona Board of Regents.
  *
  * This file is part of ndn-tools (Named Data Networking Essential Tools).
  * See AUTHORS.md for complete list of ndn-tools authors and contributors.
@@ -31,20 +31,13 @@
 namespace server {
 
 /**
- * @brief logs ping responses
+ * @brief Logs ping responses
  */
 class Tracer : noncopyable
 {
 public:
   Tracer(PingServer& pingServer, const Options& options);
 
-  /**
-   * @brief Prints ping information when interest received
-   * @param name interest name received
-   */
-  void
-  onReceive(const Name& name);
-
 private:
   const Options& m_options;
 };