void on_container_start(proton::container &c) override {
proton::source_options opts;
set_filter(opts, "colour = 'green'");
proton::connection conn = c.connect(url);
conn.open_receiver(url.path(), proton::receiver_options().source(opts));
}
void on_container_start(proton::container &c) override {
// Connection options for this connection. Merged with and overriding the container's
// client_connection_options() settings.
c.connect(url, connection_options().handler(&conn_handler).max_frame_size(2468));
}