title: Is it possible to create constructor-extension-method ? how?
body: <p>Is it possible to add a constructor extension method?</p>
  <h2>Sample Use Case</h2>
  <p>I want to add a List&lt; T &gt; constructor to receive specific amount of bytes out of a given partially filled buffer (without the overhead of copying only the relevant bytes and so on):</p>
  <pre><code>...
  public static List&lt;T&gt;(this List&lt;T&gt; l, T[] a, int n)
  {
      for (int i = 0; i &lt; n; i++)
         l.Add(a[i]);
  }
  ...
  </code></pre>
  <p>so the usage would be:</p>
  <pre><code>List&lt;byte&gt; some_list = new List&lt;byte&gt;(my_byte_array,number_of_bytes);
  </code></pre>
  <p>I've already added an AddRange extension method:</p>
  <pre><code>public static void AddRange&lt;T&gt;(this List&lt;T&gt; l, T[] a, int n)
  {
     for (int i = 0; i &lt; n; i++)
         l.Add(a[i]);
  }
  </code></pre>
  <p>I want to do it as a constructor too. Is it possible? If yes - how?</p>