static void _parameter_change_listener (void* /*arg*/, void* /*src*/, const AudioUnitEvent* event, UInt64 host_time, Float32 new_value);
void parameter_change_listener (void* /*arg*/, void* /*src*/, const AudioUnitEvent* event, UInt64 host_time, Float32 new_value);
static void _parameter_change_listener (void* /*arg*/, void* /*src*/, const AudioUnitEvent* event, UInt64 host_time, Float32 new_value);
void parameter_change_listener (void* /*arg*/, void* /*src*/, const AudioUnitEvent* event, UInt64 host_time, Float32 new_value);