what does the 'sometimes' apply to?
My main input param is typically Feature Set.
In the old tbx style i needed to have a dummy schema setup on this so that in C# code i could get a reference to the recordset and then load it with features from a json representation.
I don't see how this can be done without the schema in there.
Also, something makes me think that esri may have some tool that they use to load features into the feature set from a json representation, as that is how they go over the wire to the ags rest endpoint. but is that method exposed or in the black box of ags?