add comment documenting why we sleep

src/zm_analysis_thread.cpp

@@ -24,9 +24,9 @@ void AnalysisThread::Start() {
 void AnalysisThread::Run() {
   while (!(terminate_ or zm_terminate)) {
     // Some periodic updates are required for variable capturing framerate
-    Debug(2, "Analyzing");
     if (!monitor_->Analyse()) {
       if (!(terminate_ or zm_terminate)) {
+        // We only sleep when Analyse returns false because it is an error condition and we will spin like mad if it persists.
         Microseconds sleep_for = monitor_->Active() ? Microseconds(ZM_SAMPLE_RATE) : Microseconds(ZM_SUSPENDED_RATE);
         Debug(2, "Sleeping for %" PRId64 "us", int64(sleep_for.count()));
         std::this_thread::sleep_for(sleep_for);