int on_screen_message (afb_req_t request, const char* message);
int on_screen_reply (afb_req_t request, const char* message);
int subscribe(afb_req_t request, const char* event);
int on_screen_message (afb_req_t request, const char* message);
int on_screen_reply (afb_req_t request, const char* message);
int subscribe(afb_req_t request, const char* event);