src/main.rs</span></p>
<pre><pre class="playground"><code class="language-rust"><span class="boring">#![allow(unused)]
</span><span class="boring">fn main() {
</span>use std::thread;
use std::time::Duration;

fn simulated_expensive_calculation(intensity: u32) -&gt; u32 {
    // ゆっくり計算します
    println!(&quot;calculating slowly...&quot;);
    thread::sleep(Duration::from_secs(2));
    intensity
}
<span class="boring">}</span></code></pre></pre>
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