Client Credentials Authorization in Microsoft Flow Custom Connector
I'm trying to build a Microsoft Flow custom connector for my application (exposed via a public web API). My API uses the "client credentials" OAuth 2.0 grant type, where the user provides a client ID and client secret in their authorization request and our server sends back an access token. For the Flow connector, I would like my users to be able to enter these credentials upon spinning up a new connection which would link their instance of my application to the connector, so that way requests made using the connector will get routed to the proper instance of the app.
It seems that Flow doesn't support this out of the box, and instead requires you to enter a client ID and client secret up front, not allowing the end-user to do so. Am I missing something? I'm trying to figure out how I can make this work.