title: What is the __DynamicallyInvokable attribute for?
body: <p>Looking through <code>System.Linq.Enumerable</code> in DotPeek I notice that some methods are flavoured with a <code>[__DynamicallyInvokable]</code> attribute.</p>
  
  <p>What role does this attribute play? Is it something added by DotPeek or does it play another role, perhaps informing the compiler on how best to optimise the methods?</p>