Where does data get stored before arriving to the Staging Area ?

During the import step of a workflow profile, where does data gets stored before arriving to the staging area ?

I am using an Event Handler to manipulate loaded data before it gets saved to the staging area. However, I am unable to retrieve it before it gets stored into 'SourceStageData' Table.

Data appears in the database only after the operation named 'WriteTransformedData'.

•  Are loaded data rows stored in memory and processed, then gets saved to the table 'SourceStageData' after operation 'WriteTransformedData' ?
• How can I access the loaded data before it gets processed (parse and 1st transformation during 'Import' step) ?

Intellisense is not working on the 'Transformer' Object, so I can't search for a property/object holding loaded data: [Dim objTransformer As Transformer = DirectCast(args.Inputs(0), Transformer)]