FS-9164: [core] add Session-Per-Sec-Last to heartbeat event

src/switch_core.c

@@ -93,6 +93,7 @@ static void send_heartbeat(void)
 		switch_event_add_header(event, SWITCH_STACK_BOTTOM, "Session-Count", "%u", switch_core_session_count());
 		switch_event_add_header(event, SWITCH_STACK_BOTTOM, "Max-Sessions", "%u", switch_core_session_limit(0));
 		switch_event_add_header(event, SWITCH_STACK_BOTTOM, "Session-Per-Sec", "%u", runtime.sps);
+		switch_event_add_header(event, SWITCH_STACK_BOTTOM, "Session-Per-Sec-Last", "%u", runtime.sps_last);
 		switch_event_add_header(event, SWITCH_STACK_BOTTOM, "Session-Per-Sec-Max", "%u", runtime.sps_peak);
 		switch_event_add_header(event, SWITCH_STACK_BOTTOM, "Session-Per-Sec-FiveMin", "%u", runtime.sps_peak_fivemin);
 		switch_event_add_header(event, SWITCH_STACK_BOTTOM, "Session-Since-Startup", "%" SWITCH_SIZE_T_FMT, switch_core_session_id() - 1);