title: WASAPI capture buffer size
body: <p>I am using WASAPI in wp8.As I use <code>Getbuffer</code>method in shared mode each time it returns buffers with different size.I am capturing in 8000Hz/16bit and sometimes <code>Getbuffer</code> returns buffer with 80 samples and sometimes with 400 samples and .Is this a normal behaviour while sending different hnsBufferDuration to <code>IAudioClient::Initialize</code> doesn't have any effect in the buffer size?</p>