A developer must write a Dataverse plug-in that automatically calculates and populates a 'TotalPrice' field on the Order Line table whenever a record is created or updated. The calculation depends on the 'Quantity' and 'UnitPrice' fields on the same record, and the calculated value must be stored in the database as part of the same transaction without triggering a second update. On which pipeline stage should the plug-in step be registered to meet these requirements most efficiently?