title: How to use custom UserProvider or maybe it must be AuthenticatedProvider?
body: <p>I need to request user info from URFAClient (NetUP UTM5 billing system), but custom UserProvider's docs says that i need load user bu username without password.</p>
  
  <p>I can't do this, because all request to URFAClient must contain both username and password, i can't load userinfo without password.</p>
  
  <p>I totally confiused about how to add my very custom UserProvider, and docs says nothing about what i need.</p>
  
  <p>Any suggestion?</p>