Fix the incorrect reference type on the lambda expression

Author: EvanCui-zz

Release/include/cpprest/http_client.h

@@ -327,7 +327,7 @@ class http_client_config
     /// Sets a callback to enable custom setting of the ssl context, at construction time.
     /// </summary>
     /// <param name="callback">A user callback allowing for customization of the ssl context at construction time.</param>
-    void set_ssl_context_callback(std::function<void(boost::asio::ssl::context&)> callback)
+    void set_ssl_context_callback(const std::function<void(boost::asio::ssl::context&)>& callback)
     {
          m_ssl_context_callback = callback;
     }

Release/include/cpprest/http_listener.h

@@ -146,7 +146,7 @@ class http_listener_config
     /// Set the callback of ssl context
     /// </summary>
     /// <param name="ssl_context_callback">The function to configure a ssl context which will setup https connections.</param>
-    void set_ssl_context_callback(std::function<void(boost::asio::ssl::context&)> ssl_context_callback)
+    void set_ssl_context_callback(const std::function<void(boost::asio::ssl::context&)> &ssl_context_callback)
     {
         m_ssl_context_callback = ssl_context_callback;
     }

Release/src/http/listener/http_server_asio.cpp

@@ -480,14 +480,14 @@ void connection::async_write(ClassFuncPtr &&connection_func_ptr, const http_resp
 {
     if (m_ssl_stream)
     {
-        boost::asio::async_write(*m_ssl_stream, m_response_buf, [this, &connection_func_ptr, &response] (const boost::system::error_code& ec, std::size_t)
+        boost::asio::async_write(*m_ssl_stream, m_response_buf, [=] (const boost::system::error_code& ec, std::size_t)
         {
             (this->*connection_func_ptr)(response, ec);
         });
     }
     else
     {
-        boost::asio::async_write(*m_socket, m_response_buf, [this, &connection_func_ptr, &response] (const boost::system::error_code& ec, std::size_t)
+        boost::asio::async_write(*m_socket, m_response_buf, [=] (const boost::system::error_code& ec, std::size_t)
         {
             (this->*connection_func_ptr)(response, ec);
         });