transport: Remove unused member elementListener_.
diff --git a/include/ndn-cpp/transport/transport.hpp b/include/ndn-cpp/transport/transport.hpp
index 3be3dd3..5a23027 100644
--- a/include/ndn-cpp/transport/transport.hpp
+++ b/include/ndn-cpp/transport/transport.hpp
@@ -48,8 +48,8 @@
   
   /**
    * Process any data to receive.  For each element received, call elementListener.onReceivedElement.
-   * This is non-blocking and will silently time out after a brief period if there is no data to receive.
-   * You should repeatedly call this from an event loop.
+   * This is non-blocking and will return immediately if there is no data to receive.
+   * You should normally not call this directly since it is called by Face.processEvents.
    * @throw This may throw an exception for reading data or in the callback for processing the data.  If you
    * call this from an main event loop, you may want to catch and log/disregard all exceptions.
    */