Set the raw binary content of the stream.
Compression settings are unaltered. So if - for example - you
have a stream which is Flate compressed you must use SetData with
Flate compressed data.
For this reason you may wish to call ClearData before using SetData.
Using the overload which accepts a StreamObject is equivalent
to, but more efficient than, getting the data from the source
StreamObject and then using SetData to assign it to this one.