title: What does exclamation mark mean before invoking a method in C# 8.0?
body: <p>I have found a code written in C# seemingly version 8.0. In the code, there is an exclamation mark before invoking a method. What does this part of the code mean, and above all, what are its uses?</p>
  
  <pre><code>var foo = Entity!.DoSomething();
  </code></pre>