title: Where is the source code from 'private extern String PadHelper'
body: <p>When I was looking for the following source code in .NET source code, I didn't find source for <a href="https://referencesource.microsoft.com/#mscorlib/system/string.cs,70aae718a1936b02,references" rel="nofollow noreferrer"><code>PadHelper</code></a> that is the method inside <code>PadLeft</code> and <code>PadRight</code>. </p>
  
  <p>Is there something wrong with my search?</p>
  
  <pre><code>[System.Security.SecuritySafeCritical]  // auto-generated
  [ResourceExposure(ResourceScope.None)]
  [MethodImplAttribute(MethodImplOptions.InternalCall)]
  private extern String PadHelper(int totalWidth, char paddingChar, bool isRightPadded);
  </code></pre>