Add ability to unregister audio callback

include/boo/audiodev/IAudioVoiceEngine.hpp

@@ -38,6 +38,9 @@ struct IAudioVoiceEngine
     /** Client may optionally register a 200-virtual-updates each second callback for the stream */
     virtual void register5MsCallback(std::function<void(double dt)>&& callback)=0;
 
+    /** Unregister callback for stable cleanup */
+    virtual void unregister5MsCallback()=0;
+
     /** Client may use this to determine current speaker-setup */
     virtual AudioChannelSet getAvailableSet()=0;
 

lib/audiodev/AudioVoiceEngine.cpp

@@ -202,6 +202,11 @@ void BaseAudioVoiceEngine::register5MsCallback(std::function<void(double dt)>&&
     m_5msCallback = std::move(callback);
 }
 
+void BaseAudioVoiceEngine::unregister5MsCallback()
+{
+    m_5msCallback = {};
+}
+
 void BaseAudioVoiceEngine::setVolume(float vol)
 {
     m_totalVol = vol;

lib/audiodev/AudioVoiceEngine.hpp

@@ -69,6 +69,7 @@ public:
     std::unique_ptr<IAudioSubmix> allocateNewSubmix(bool mainOut, IAudioSubmixCallback* cb, int busId);
 
     void register5MsCallback(std::function<void(double dt)>&& callback);
+    void unregister5MsCallback();
 
     void setVolume(float vol);
     const AudioVoiceEngineMixInfo& mixInfo() const;