stFrom.html">castFrom</a></span><span class="signature">&lt;S, T&gt;</span><span class="signature">(<wbr><span class="parameter" id="castFrom-param-source"><span class="type-annotation"><a href="dart-core/Set-class.html">Set</a><span class="signature">&lt;S&gt;</span></span> <span class="parameter-name">source</span>, {</span> <span class="parameter" id="castFrom-param-newSet"><span class="type-annotation"><a href="dart-core/Set-class.html">Set</a><span class="signature">&lt;R&gt;</span></span> <span class=