title: Does NSFileWrapper load everything into memory?
body: <p>Lets say I have an <code>NSFileWrapper</code> directory. This directory is made up of several levels of directories and files. Some of the files are large. Are all these files loaded into memory, or are they lazily loaded?</p>
  
  <p>If they are loaded into memory, are there any alternatives to <code>NSFileWrapper</code> with similar functionality that won't load files into memory? Something I can hook into <code>UIDocument</code>?</p>
  
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  <p>This is for a document based application, which uses <code>UIDocument</code>'s that are synced with iCloud. A document can have images and videos embedded inside it. Each image/video has a preview image (thumbnail) that is shown in an HTML document. The full size images or videos shouldn't be loaded into memory, but rather loaded on demand.</p>
  
  <p>I also need a way to add a resource without loading it into memory. Something like "initWithAsset:(ALAsset *)" would be ideal.</p>