I used the sample code titled "Use Third Party Storage in and add-in" in a add-in of mine.  I have been using it for quite some time now without any problems.  However, when I upgraded to SW 2015 I get an error in the ComStream class in this line:

        public override void Flush()

        {

            if (theOrigStream == null)

            {

                throw new ObjectDisposedException("theStream");

            }

            theOrigStream.Commit(0);

        }

        public override void Close()

        {

            if (!(theOrigStream == null))

            {

                theOrigStream.Commit(0);

                Marshal.ReleaseComObject(theOrigStream);

                theOrigStream = null;

                GC.SuppressFinalize(this);

            }

        }

The error occurs in this call:  theOrigStream.Commit(0)

It gives the error: "The method or operation is not implemented."

I don't really understand what it is supposed to do so I don't know how to fix it.  Any help would be appreciated.