internal override void SetNextOutputBuffer( Array buffer, int index, int count ) {
Debug.Assert( buffer != null );
Debug.Assert( count >= 0 );
Debug.Assert( index >= 0 );
Debug.Assert( buffer.Length - index >= count );
Debug.Assert( ( buffer as byte[] ) != null );
this.buffer = (byte[])buffer;
this.startIndex = index;
this.curIndex = index;
this.endIndex = index + count;
}