Represents a collection of CQGFill objects.

All fills of an order are stored in this collection, each one represented as a CQGFill object. If one fill is overridden by another, both will be stored in the collection.
Access to an item in this collection can be made based on either CQGFill.Id or its sequential index.
See Accessing non-existent collection items for details on accessing items that do not exist in the collection.
See the usage of CQG API collections in the InstrumentChanged event's example section.
See the usage of CQGFill properties in the OrderChanged event's example section.