asio: Add const qualifier to client::session member functions

src/asio_client_session.cc

@@ -49,24 +49,28 @@ session::session(boost::asio::io_service &io_service,
 
 session::~session() {}
 
-void session::on_connect(connect_cb cb) { impl_->on_connect(std::move(cb)); }
+void session::on_connect(connect_cb cb) const {
+  impl_->on_connect(std::move(cb));
+}
 
-void session::on_error(error_cb cb) { impl_->on_error(std::move(cb)); }
+void session::on_error(error_cb cb) const { impl_->on_error(std::move(cb)); }
 
-void session::shutdown() { impl_->shutdown(); }
+void session::shutdown() const { impl_->shutdown(); }
 
-boost::asio::io_service &session::io_service() { return impl_->io_service(); }
+boost::asio::io_service &session::io_service() const {
+  return impl_->io_service();
+}
 
 const request *session::submit(boost::system::error_code &ec,
                                const std::string &method,
-                               const std::string &uri, header_map h) {
+                               const std::string &uri, header_map h) const {
   return impl_->submit(ec, method, uri, read_cb(), std::move(h));
 }
 
 const request *session::submit(boost::system::error_code &ec,
                                const std::string &method,
                                const std::string &uri, std::string data,
-                               header_map h) {
+                               header_map h) const {
   return impl_->submit(ec, method, uri, string_reader(std::move(data)),
                        std::move(h));
 }
@@ -74,7 +78,7 @@ const request *session::submit(boost::system::error_code &ec,
 const request *session::submit(boost::system::error_code &ec,
                                const std::string &method,
                                const std::string &uri, read_cb cb,
-                               header_map h) {
+                               header_map h) const {
   return impl_->submit(ec, method, uri, std::move(cb), std::move(h));
 }
 

src/includes/nghttp2/asio_http2_client.h

@@ -97,22 +97,22 @@ public:
           const std::string &service);
   ~session();
 
-  void on_connect(connect_cb cb);
-  void on_error(error_cb cb);
+  void on_connect(connect_cb cb) const;
+  void on_error(error_cb cb) const;
 
-  void shutdown();
+  void shutdown() const;
 
-  boost::asio::io_service &io_service();
+  boost::asio::io_service &io_service() const;
 
   const request *submit(boost::system::error_code &ec,
                         const std::string &method, const std::string &uri,
-                        header_map h = {});
+                        header_map h = {}) const;
   const request *submit(boost::system::error_code &ec,
                         const std::string &method, const std::string &uri,
-                        std::string data, header_map h = {});
+                        std::string data, header_map h = {}) const;
   const request *submit(boost::system::error_code &ec,
                         const std::string &method, const std::string &uri,
-                        read_cb cb, header_map h = {});
+                        read_cb cb, header_map h = {}) const;
 
 private:
   std::unique_ptr<session_impl> impl_;