Closes the stream and calls Close() on the Subclass. This usually results in the closing of the file (or stream), and flushing any data in buffers. Also, any temporary or state information is usually cleared. The SubClass will be destroyed however. If a call to Close is not made, and a subsequent call to Open is made, then the same subclass will be used. This will allow setting of Stream options in one module and then reading the image in another.
Resets internal properties, Releases the Subclass
McStream Properties are persisted on a call to Close()