title: Why do I get "System is not running" error after upgrading actix-rt to 2.0.2?
body: <p>I attempted to update to actix_rt 2.0.2 and have since been getting the following error:</p>
  <pre class="lang-none prettyprint-override"><code>thread 'main' panicked at 'System is not running'
  </code></pre>
  <p>Here is my minimal example:</p>
  <pre class="lang-toml prettyprint-override"><code># Cargo.toml
  [dependencies]
  actix = &quot;0.10&quot;
  actix-web = { version = &quot;3.3.2&quot;, default-features = false }
  actix-rt = &quot;2.0.2&quot;
  </code></pre>
  <pre><code>//! main.rs
  use actix_rt;
  use actix_web::{HttpServer, App, HttpResponse};
  
  async fn hello() -&gt; HttpResponse {
      HttpResponse::Ok().finish()
  }
  
  #[actix_rt::main]
  async fn main() -&gt; std::io::Result&lt;()&gt; {
      let server = HttpServer::new(move || {
          App::new().route(&quot;/&quot;, actix_web::web::get().to(hello))
      });
      server.bind(&quot;127.0.0.1:8080&quot;)?.run().await
  }
  </code></pre>
  <p>I'm assuming it must be some version incompatibilities between the actix crates. I need actix_rt 2.0.x so that I can integrate with <a href="https://crates.io/crates/criterion" rel="nofollow noreferrer">Criterion</a>.</p>
  <p>Is there a combination of version numbers to get these to work together?</p>