SarAsio: don't broadcast format changes on Windows 10 and later

Whenever any audio endpoint became active, SarAsio had the driver send
KSEVENT_PINCAPS_FORMATCHANGE to every SAR filter on its next tick, and
the audio engine invalidated every stream open on a SAR endpoint. The
comment says new and non-SAR endpoints are filtered out, but the
property check passes for any endpoint, so starting a host invalidated
its own fresh streams, and so did each endpoint Windows rebuilt or any
other device appearing.

The event exists so the audio engine re-reads the format of an endpoint
re-created with a different sample rate. On Windows 10 and later the
driver puts the channel count, sample rate and sample size into the
endpoint's KS reference string, so such an endpoint is a new endpoint
to Windows and the event is never needed there. Skip it on those
versions.

On the test VM (16 endpoint pairs, three start/stop iterations), the
loopback run saw 34 to 116 stream invalidations per run with the
broadcast (3 runs) and none without it (8 runs).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: eiz

SarAsio/sarclient.cpp

@@ -580,6 +580,26 @@ void SarClient::mux(
     }
 }
 
+// On Windows 10 and later the driver puts each endpoint's channel count,
+// sample rate and sample size into its KS reference string (see
+// SarCreateEndpoint), so an endpoint whose format changed is a new endpoint
+// to Windows and no format change event is needed.
+static bool endpointIdIncludesFormat()
+{
+    typedef LONG (WINAPI *RtlGetVersionFn)(PRTL_OSVERSIONINFOW);
+    static const bool result = [] {
+        RTL_OSVERSIONINFOW info = {};
+        auto rtlGetVersion = (RtlGetVersionFn)GetProcAddress(
+            GetModuleHandleW(L"ntdll.dll"), "RtlGetVersion");
+
+        info.dwOSVersionInfoSize = sizeof(info);
+        return rtlGetVersion && rtlGetVersion(&info) == 0 &&
+            info.dwMajorVersion >= 10;
+    }();
+
+    return result;
+}
+
 HRESULT STDMETHODCALLTYPE SarClient::NotificationClient::OnDeviceStateChanged(
     _In_  LPCWSTR pwstrDeviceId,
     _In_  DWORD dwNewState)
@@ -591,7 +611,7 @@ HRESULT STDMETHODCALLTYPE SarClient::NotificationClient::OnDeviceStateChanged(
     // KSEVENT_PINCAPS_FORMATCHANGE event, which causes the audio engine to
     // re-query the pin capabilities. This isn't needed for newly added
     // endpoints or non-SAR endpoints, so we filter out those events.
-    if (dwNewState != DEVICE_STATE_ACTIVE) {
+    if (dwNewState != DEVICE_STATE_ACTIVE || endpointIdIncludesFormat()) {
         return S_OK;
     }