title: C# using namespace directive in nested namespaces
body: <p>Right, I've usually used 'using' directives as follows</p>
  
  <pre><code>using System;
  using System.Collections.Generic;
  using System.Linq;
  using System.Text;
  
  namespace AwesomeLib
  {
    //awesome award winning class declarations making use of Linq
  }
  </code></pre>
  
  <p>i've recently seen examples of such as </p>
  
  <pre><code>using System;
  using System.Collections.Generic;
  using System.Linq;
  using System.Text;
  
  namespace AwesomeLib
  {
    //awesome award winning class declarations making use of Linq
  
    namespace DataLibrary
    {
      using System.Data;
  
      //Data access layers and whatnot
    }
  
  }
  </code></pre>
  
  <p>Granted, i understand that i can put USING inside of my namespace declaration. Such a thing makes sense to me if your namespaces are in the same root (they organized).</p>
  
  <pre><code>System;
  namespace 1 {}
  namespace 2 
  {
    System.data;
  }
  </code></pre>
  
  <p>But what of nested namespaces?  Personally, I would leave all USING declarations at the top where you can find them easily.  Instead, it looks like they're being spread all over the source file.</p>
  
  <p>Is there benefit to the USING directives being used this way in nested namespaces? Such as memory management or the JIT compiler?</p>