Value is an NSData instance containing the data written to a memory stream.
Use this property when you have an output-stream object instantiated to collect written data in memory. The value of this property is read-only.
Available in Mac OS X v10.3 and later.
Declaration Syntax Version Information- Available in Monobjc Bridge: 10.6 (For Mac OS X 10.6 and later), 10.5 (For Mac OS X 10.5 and later)