title: Import header file when debug in lldb
body: <p>Now we can import module </p>
  
  <pre><code>(lldb) expr @import UIKit
  </code></pre>
  
  <p>What's the meaning of this <code>import</code>? What happen to debugger when we import a module.</p>
  
  <p>Can we use this to import some private header file in a static lib, and how？</p>