title: Does JsonStringEnumConverter (System.Text.Json) support null values?
body: <p>I am shifting my code from .NET Core 2.x to .NET Core 3.x (i.e. use the native library <code>System.Text.Json</code>). In doing this, I ran into some issues with how the former <code>Newtonsoft.Json</code> support for nullable enums does not have a clear migration path at the moment --- it looks like it is not supported in .NET Core 3.x?.</p>
  
  <p>For example, using <code>Newtonsoft.Json</code>, the JSON converter supported nullable enums, like so:</p>
  
  <pre><code>public enum UserStatus
  {
      NotConfirmed,
      Active,
      Deleted
  }
  
  public class User
  {
      public string UserName { get; set; }
  
      [JsonConverter(typeof(StringEnumConverter))]  // using Newtonsoft.Json
      public UserStatus? Status { get; set; }       // Nullable Enum
  }
  </code></pre>
  
  <blockquote>
    <p>The current version of the native library <code>System.Text.Json</code>, does not seem to support this.</p>
  </blockquote>
  
  <p><strong>How do I solve this problem?</strong> I cannot migrate my code!</p>