Represents a collection of CQGAccount objects.

The collection is filled only on CQG Gateway logon. New accounts will not be added to this collection at run time.
Access to an item in this collection can be made based on either the account Gateway ID or the Account FCM ID / FCM ID pair.
See Accessing non-existent collection items for details on accessing items that do not exist in the collection.
See the usage of CQGAccounts collection in the AccountChanged event's example section.