AUDCLNT_BUFFERFLAGS_SILENT not handled

[ErwanLegrand]

Per Microsoft's specifications, it is the applications responsibility to zero the buffer when a driver returns AUDCLNT_BUFFERFLAGS_SILENT.

https://learn.microsoft.com/en-us/windows/win32/api/audioclient/ne-audioclient-_audclnt_bufferflags

I have a hardening PR for WASAPI in preparation which fixes this issue amongst other things.

[roderickvd]

Good one. Reading the docs it actually sounds like we should just ignore the buffer and return all silence (which is slightly different than zeroing the buffer):

Treat all of the data in the packet as silence and ignore the actual data values

[roderickvd]

I had several local WASAPI changes cooking, to which I added this: #1379