When using the pass-through router, if you want to return a response, you must set synchronous to "true" on the outbound endpoint.

当使用pass - through路由器时，如果想返回一个响应，必须将出站端点的synchronous属性设置为true。

youdao

He prodded the ball through to Jean-Claude Darcheville, who timed his return pass to perfection.

BBC: Rangers 1-0 Celtic

The YHT-697BL features HDMI 4K and 3D video pass-through with Audio Return Channel (ARC) and Yamaha's proprietary CINEMA DSP 3D audio to ensure that the system will deliver superior home theater experiences for years to come.

ENGADGET: Yamaha YHT-697 home theater in a box brings AirPlay, iPad connectivity to the masses