anchor.diff:      addLayerToMap(markerClusterGroup)
   
       lastUpdatedAt = $.now()
  -    setTimeout((-> addMarkerLayer(markers, markerClusterGroup, lastUpdatedAt)), dataPollDelay)
  +    @dataPollPromise = setTimeout((-> addMarkerLayer(markers, markerClusterGroup, lastUpdatedAt)), dataPollDelay)
   
   @initializeMarkerForSession = (session) ->
     marker = L.marker(
  
positive.code:       heatLayer = L.heatLayer(heats, {radius: 20})
        addLayerToMap(heatLayer)
  
      setTimeout((-> addHeatLayer(heatLayer)), dataPollDelay)
  
  @sessionToHeat = (session) ->
    [session.spot.location.lat, session.spot.location.lng, session.number_of_jumps]
  
negative.code:   @map.on 'popupclose', (e) -> setWindDate(new Date)
  
    # When requesting sessions, convert the timestamp from milliseconds to seconds
    $.get '/sessions', ({last_updated_at: (lastUpdatedAt / 1000).toFixed()} if lastUpdatedAt?), (sessions) =>
      for session in sessions
        markers.push(initializeMarkerForSession(session))
  
  