title: How can I get amount of "free" memory in Unity3d on iOS?
body: <p>I have a problem: if I try to create a screenshot with <a href="http://docs.unity3d.com/Documentation/ScriptReference/Texture2D.ReadPixels.html" rel="nofollow">Texture2D.ReadPixels</a>, the game crashes on some devices (most notably, iPod 4G). Supposedly, it happens because of low memory. Before creating screenshot, I want to detect, if I can allocate the required amount of memory safely, and show the warning to the player if I suppose I will crash.</p>
  
  <p>However, it seems that resources like textures are managed outside of Mono VM. System.GC.GetTotalMemory returns 9mb, when I have atlases as big as 16mb. So, it seems that I have to write a plugin for that.</p>
  
  <p>(There was a section describing that I didn't receive low memory warnings, but it seems that I was mistaken about it, and on Objective-C level, the warnings are successfully raised).</p>
  
  <p>How can I get the amount of "free" memory that I can allocate without crashing? May be there's some other way to achieve the functionality I want?</p>