What happens upon mmdevapi capture overrun on native?

[Joerg-Cyril.Hoehle at t-systems.com]

Hi,

>> A. mmdevapi fills the whole buffer once.
>> B. mmdevapi continuously overwrites the circular buffer.
>> I think A makes sense but really I don't know.
>I suspect B

I realized that I don't need a microphone if I can trust
IAC_CaptureClient's pu64QPCPosition output parameter: "the value of
the performance counter at the time that the audio endpoint device
recorded the device position of the first audio frame in the data
packet."

Modifying the capture tests to trace that value shows that mmdevapi
mostly implements behaviour A with a few quirks.  Please visit bug
#30147 for details.

Regards,
	Jörg Höhle