When the interface identified by iid is queried for, COM_INTERFACE_ENTRY_AGGREGATE forwards to punk.
[in] The GUID of the interface queried for.
[in] The name of an IUnknown pointer.
The punk parameter is assumed to point to the inner unknown of an aggregate or to NULL, in which case the entry is ignored. Typically, you would CoCreate the aggregate in FinalConstruct.
See COM_INTERFACE_ENTRY Macros for remarks about COM map entries.