Add forwarding hint support

Change-Id: Ie8a1d45f3abe0377a3b6c0cff08d27824b2861b1
diff --git a/src/requester-request.hpp b/src/requester-request.hpp
index acd06cc..9291958 100644
--- a/src/requester-request.hpp
+++ b/src/requester-request.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2017-2021, Regents of the University of California.
+ * Copyright (c) 2017-2022, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -249,6 +249,10 @@
    */
   Name m_issuedCertName;
   /**
+   * @brief The optional forwarding hint.
+   */
+  Name m_forwardingHint;
+  /**
    * @brief ecdh state.
    */
   ECDHState m_ecdh;