 to be a primitive type.
<p>

    It is more efficient in general, the  API is the same with <a href="Belt.HashSet.html"><code class="code">Belt.HashSet</code></a> except its key type is fixed,
    and identity is not needed(using the built-in one)
<p>

    <b>See</b> <a href="Belt.HashSet.html"><code class="code">Belt.HashSet</code></a><br>
 
                    </div>
                    
                    </div>

                  <hr width="100%">
<div class="type-declaration">
<pre><span id="TYPEkey"