title: .Net Core 3.1 dynamic object of type JsonElement
body: <p>We're migrating an Asp.Net Framework project to .Net Core 3.1. The sites uses SignalR and payload are sent from the frontend and received as dynamic object at the backend: </p>
  
  <p><strong>Frontend</strong>:</p>
  
  <pre class="lang-js prettyprint-override"><code>var hostData = {
      "foo": "Bar"
  };
  
  connection.invoke("echo", hostData);
  </code></pre>
  
  <p><strong>Backend</strong>:</p>
  
  <pre class="lang-cs prettyprint-override"><code>public async Task echo(dynamic data)
  {
      var fooValue = data.foo;  
  }
  </code></pre>
  
  <p>This worked fine in .Net Framework but in .Net Core 3.1 it becomes a object (System.Text.JsonElement). I know I can use a strongly typed object instead, but as I don't want to update all methods, I'd rather keep it as a dynamic. - Is this possible?</p>