Learning to develop an IDP extension

[Yeargan, Yancey]

I have a need to develop an extension to Shibboleth Identity Provider 3.2+ to interface with Microsoft's on-premise multi-factor authentication server. 

I am currently reading through the documentation available at https://wiki.shibboleth.net/confluence/display/IDP30/DeveloperResources but feel that I would learn much faster if I were able to reference a concrete example. 

Has anyone done similar and have an authentication related extension (perhaps dealing with MFA) that I could review and possibly adapt?

--Yancey