public int UnregisterEndpointNotificationCallback([NativeTypeName("IMMNotificationClient *")] IMMNotificationClient *pClient)
 {
     return(((delegate * unmanaged <IMMDeviceEnumerator *, IMMNotificationClient *, int>)(lpVtbl[7]))((IMMDeviceEnumerator *)Unsafe.AsPointer(ref this), pClient));
 }
 public HRESULT RegisterEndpointNotificationCallback(IMMNotificationClient *pClient)
 {
     return(((delegate * unmanaged <IMMDeviceEnumerator *, IMMNotificationClient *, int>)(lpVtbl[6]))((IMMDeviceEnumerator *)Unsafe.AsPointer(ref this), pClient));
 }