title: ARCGIS iOS - map layers memory issue
body: <p>In my application I used arcgis sdk. I have 3 different map so I used 3 tiled map service layers. And also I have a graphic layer to show symbol for selected specific region on the map. My app; first connects the services with credential and then adds the layers to the map view. So far there is no problem. After loading all of layers, I started to use AGSQueryTask and AGSIdentify task for some query operations. Here the problem starts. The debugger gives me  "Received memory warning. Level=1". I continue to do zoom/pan, and extra query operations. After a while, my app crashes giving no error. I reviewed my code, googled about my problem, looked around in arcgis forums however I didn't find a solution and good explanation. I tried my app with 1 map not 3 but the warning and crashing didn't disappear. I also deal with hidden property of layer view again there is no improvement.</p>
  
  <p>After all, is there anyone who knows a solution or an explanation or an assumption to my memory problem?</p>
  
  <p>P.S. I also debugged my code with nszombienabled and guard malloc thanks to stackoverflow:) In  this process I came across ": CGBitmapContextInfoCreate: unable to allocate .. bytes for bitmap data". Is my memory problem related to this error?</p>
  
  <p>Thanks in advance.</p>