Previously, if you wanted to export an Inventor document to *.rfa (Revit family file type) on Automation API for Inventor then you had to export to a format that Revit understands, and then pass it to a Automation API for Revit work item to produce a Revit family file from it.
Now you can achieve all that directly on Automation API for Inventor since Revit Core Engine (which is used by the BIM Content add-in) is now available on that service too.
Example:
You can have a look at the sample: https://inventor-config-demo.autodesk.io/
And see how this was done, refer to the source code here:
https://github.com/Autodesk-Forge/forge-configurator-inventor/blob/master/AppBundles/RFAExportRCEPlugin/RFAExportRCEAutomation.cs