System.IO.Stream that can be used for document content. If content
is not null, the stream is initialized with the specified content. It is prefered to use
this method to obtain a stream over creating your own if the source of the content does
not already provide one. The returned streams are optimized for memory usage and performance.
The position is set to the beginning of the stream when returned.
Stream GetContentStream(string content = null)
||Content to initialize the stream with.
||A stream for document content.