Use async logging while streaming only

The benefits of reliable output outweigh performance concerns during non-streaming activities.

app/streaming/session.cpp

@@ -2014,6 +2014,9 @@ void Session::execInternal()
     // Toggle the stats overlay if requested by the user
     m_OverlayManager.setOverlayState(Overlay::OverlayDebug, m_Preferences->showPerformanceOverlay);
 
+    // Switch to async logging mode when we enter the SDL loop
+    StreamUtils::enterAsyncLoggingMode();
+
     // Hijack this thread to be the SDL main thread. We have to do this
     // because we want to suspend all Qt processing until the stream is over.
     SDL_Event event;
@@ -2363,6 +2366,9 @@ void Session::execInternal()
     }
 
 DispatchDeferredCleanup:
+    // Switch back to synchronous logging mode
+    StreamUtils::exitAsyncLoggingMode();
+
     // Uncapture the mouse and hide the window immediately,
     // so we can return to the Qt GUI ASAP.
     m_InputHandler->setCaptureActive(false);

app/streaming/streamutils.cpp

@@ -417,3 +417,15 @@ int StreamUtils::getDrmFd(bool preferRenderNode)
 
     return -1;
 }
+
+extern QAtomicInt g_AsyncLoggingEnabled;
+
+void StreamUtils::enterAsyncLoggingMode()
+{
+    g_AsyncLoggingEnabled.ref();
+}
+
+void StreamUtils::exitAsyncLoggingMode()
+{
+    g_AsyncLoggingEnabled.deref();
+}

app/streaming/streamutils.h

@@ -31,4 +31,10 @@ public:
 
     static
     int getDrmFd(bool preferRenderNode);
+
+    static
+    void enterAsyncLoggingMode();
+
+    static
+    void exitAsyncLoggingMode();
 };