an>
<span class="kw">pub</span> <span class="kw">trait</span> <span class="ident">CountDown</span> {
    <span class="comment">// ..</span>

    <span class="doccomment">/// &quot;waits&quot; until the count down is over</span>
    <span class="kw">fn</span> <span class="ident">wait</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">nb</span>::<span class="prelude-ty">Result</span><span