[F.Rq.] Somehow store audio samples to be played in reverse while rewinding

Right now, RetroArch uses a trick that makes rewind savestates have reversed audio output client-side. BizHawk does not do this, causing rewind to have messy audio. However, this isn't true if you open Libretro's TGB Dual core in BizHawk (should never be accepted on TASVideos), as the captured audio output is reversed already. But on RetroArch the client and the core does the same thing too, so the messy audio persists. So the question is, why BizHawk's cores don't do this?

Start by tracing how BizHawk captures and plays audio during rewind, then compare that behavior with RetroArch and Libretro's TGB Dual core as described in the issue. Determine whether cores or the client should reverse captured samples, and document a concrete completion criterion before attempting implementation.