Class wrapping a marshalled object whose type is unknown locally.
If an object is returned by a method invoked over drb, but the class of the object is unknown in the client namespace, or the object is a constant unknown in the client namespace, then the still-marshalled object is returned wrapped in a DRbUnknown instance.
If this object is passed as an argument to a method invoked over drb, then the wrapped object is passed instead.
The class or constant name of the object can be read from the name attribute. The marshalled object is held in the buf attribute.