Utility stream wrapper type
TStreamWrapper 'wraps' an existing stream, redirecting all TIO method calls to the wrapped stream.
This can be useful for writing stream 'filters' that modify the behaviour of existing streams.
Note that the Close method causes the underlying stream to be closed, which may not always be desirable. If necessary, you should override Close with a NOP version.
Method SetStream( stream:TStream )
Set underlying stream
Sets the stream to be 'wrapped'. All calls to TIO methods of this stream will be redirected to stream.