ISimpleAudioVolumeVtable.SetMasterVolume

Undocumented in source but is binding to Windows. You might be able to learn more by searching the web for its name.
struct ISimpleAudioVolumeVtable
extern (Windows) @nogc nothrow
HRESULT function(This_, float fLevel, LPCGUID EventContext) SetMasterVolume;

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