title: Session: Cannot convert int to byte[] in ASP.NET Core 3.0 C#
body: <p>I tried to look up how to use the new way of using sessions in core 3.0.</p>
  
  <p>It goes like:
  <code>HttpContext.Session.Set("UserID", ???);</code>, except I can't fill in an int. </p>
  
  <p>I tried to look it up on the official microsoft site, but that one only had <code>HttpContext.Session.SetInt32</code> or <code>HttpContext.Session.SetString</code>.</p>
  
  <p>How do you use the new set from core 3.0?</p>