s object. 
                  <div class="features">inherited</div>
</dd>
        <dt id="union" class="callable inherited">
          <span class="name"><a href="../dart-core/Set/union.html">union</a></span><span class="signature">(<wbr><span class="parameter" id="union-param-other"><span class="type-annotation"><a href="../dart-core/Set-class.html">Set</a><span class="signature">&lt;<wbr><span class="type-parameter">E</span>&gt;</span></span> <span class="parameter-name">other</span></span><wbr>)
         