title: Insert OIDC IDP into existing SP SAML connection
body: <p>Currently I have an SP that relies on a SAML identity provider. It also supports users logging in directly to the SP. User can login directly or user can start at SP and be redirected to SAML identity provider for authentication.</p>
  
  <p>I am planning on converting the SP to use OIDC and IdSrv4 and not having SP managed credentials at all. I'd like to still support the SAML provider, but ideally thru the new OIDC IdP. What is the proper way to add this new OIDC IdP into the SAML flow? Do I:</p>
  
  <ol>
  <li>Have SP and SAML communicate and then pass on SAML response to IdP to translate (this does not seem correct and open to abuse)</li>
  <li>Have SP redirect to OIDC IdP with some context to know to go to SAML. Then OIDC IdP handles the SAML response and goes thru regular OIDC flows to SP.
  
  <ol>
  <li>What is best practice to tell IdP to use (redirect to) a certain SAML IdP in certain contexts and prompting for OIDC IdP creds in other contexts?</li>
  </ol></li>
  <li>Keep SP using SAML IdP and also have it use OIDC IdP?</li>
  <li>Something else?</li>
  </ol>