This class provides methods for supporting Uniform Data Transfer and managing connections.
IDataObject also manages connections to advise sinks to handle data change notifications. In order for the client to receive data change notifications from the data object, the client must implement the IAdviseSink interface on an object called an advise sink. When the client then calls IDataObject::DAdvise, a connection is established between the data object and the advise sink.
Class IDataObjectImpl provides a default implementation of IDataObject and implements IUnknown by sending information to the dump device in debug builds.