What is the meaning of in modifier in the parameter list?
<p>I saw the following usage of in:</p>

<p><a href="http://stackoverflow.com/questions/2662369/covariance-and-contravariance-real-world-example">Covariance and contravariance real world example</a></p>

<pre><code>interface IGobbler&lt;in T&gt; {
    void gobble(T t);
}
</code></pre>

<p>I don't understand what the usage of <strong>in</strong> stands for. Does it have relationship with <em>ref</em>, <em>out</em>??</p>
