Add stream stats modulo to config file

sf-stream/include/stream_config.hpp

@@ -14,4 +14,7 @@ namespace stream_config
     const int PULSE_ZMQ_SNDHWM = 100;
     // Number of times we try to re-sync in case of failure.
     const int SYNC_RETRY_LIMIT = 3;
+
+    // Number of pulses between each statistics print out.
+    const size_t STREAM_STATS_MODULO = 10000;
 }