title: How to convert UnsafePointer<CUnsignedChar> to String?
body: <p>I have tried this method:</p>
  
  <pre><code>String.stringWithCString(cString: UnsafePointer&lt;CChar&gt;, encoding: NSStringEncoding)
  </code></pre>
  
  <p>But unfortunately, it only work with <code>UnsafePointer&lt;CChar&gt;</code>. And I have no idea about how to convert <code>UnsafePointer&lt;CUnsignedChar&gt;</code> to <code>UnsafePointer&lt;CChar&gt;</code>.  </p>