code: function SetGarbage (proxy, timeout) {
      // let's call back ourself after timeout*1000/4
      proxy.Debug (4, "SetGarbage timeout=%d", timeout);
      setTimeout (function(){SetGarbage (proxy, timeout);}, timeout*500);
      
      // let compute timeout timeout limit
      var lastshow = new Date().getTime() - (timeout *1000);
      
      for (var mmsi in proxy.vessels) {
          var vessel = proxy.vessels[mmsi];
          if (vessel.lastshow < lastshow) {
              proxy.Debug (5, "Removed Vessel mmsi=%s", mmsi);
              delete proxy.vessels [mmsi];
          }
      }
        
  }
docs: this function scan active device table and remove dead one based on inactivity timeout