title: System.IO.MemoryMappedFiles on MonoTouch?
body: <p>I wanted to convert a small test application from Windows .NET 4 to MonoTouch but I am missing <code>System.IO.MemoryMappedFiles</code>. 
  Then I tried it with a plain Mono console app and the namespace isn't there either. 
  I tried Mono 2.10 in combination with MonoDevelop 2.4.</p>
  
  <p>Is it supposed to be there or not? I'm kind of confused, as .NET4 compatibility was announced with Mono, as far as I know.</p>