iOS Bundle-loading memory, on loading text-asset

I have a large xml file which is loaded from a TextAsset in an asset bundle, once loaded I parse the elements and use the data contained to create a database of objects with various features and parameters.

There is a surprisingly large memory spike when I assign the TextAsset.text to a string, or read it using a string reader. I can manage all memory increases due to the bundle itself, by unloading the bundle, unloading unused assets and destroying the text asset. but nothing I do seems to get rid of the increase created by assigning the TextAsset.Text to a string. I've added the code snippet I'm testing below.


This part works just fine, the memory used by loading the bundle request and the Text asset is released when I destroy the textasset and unload unused assets

Code (CSharp):

1. if (bundle.mainAsset != null)
2.                 {
3.                     AssetBundleRequest request = bundle.LoadAssetAsync("data", typeof(TextAsset));
4.  
5.                     yield return request;
6.  
7.                     TextAsset xmlFile = request.asset as TextAsset;

The Parser.Xml is a string, I've also tried directly loading it to an XMLDoc, and using a stringReader, once it loads the text into the string, the memory goes up and will not go down no matter what I do after

Code (CSharp):

1. parser.Xml = xmlFile.text;

This is more or less everything I could think of to release the memory

Code (CSharp):

1.                     parser.Xml = null;
2.                     DestroyImmediate(xmlFile,true);
3.                     System.GC.Collect();
4.                     request = null;
5.                     bundle.Unload(true);
6.                     Resources.UnloadUnusedAssets();
7.  
8.        }

I'm not really sure if its a memory leak or if I'm missing something here, this issue seems to only happen on iOS device (profiled using instruments). Don't see any evidence of it when I profile memory in editor

 

It is worth to note that the data xml file is 20+ mb.

 

bump =(