CPersistStream Class

CPersistStream is the base class for persistent properties of filters (that is, filter properties in saved graphs).

The simplest way to use CPersistStream is to:

1. Arrange for your filter to inherit this class.
2. Implement WriteToStream and ReadFromStream in your class. These will override the functions here, which do nothing but act as placeholders.
3. Change your NonDelegatingQueryInterface to handle IPersistStream.
4. Implement SizeMax to return an upper bound on the number of bytes of data you save.

   If you save Unicode™ data, remember that a WCHAR is 2 bytes.

5. When your data changes, call SetDirty.