Mantain a reference to underlying python stream.
Mantain a reference to underlying python stream.

Before, we were tacitely assuming that the stream passed to BinaryWriter
would have been maintained alive by the instantiating context.

crs4/pydoop,elzaggo/pydoop,crs4/pydoop,crs4/pydoop,elzaggo/pydoop,elzaggo/pydoop,elzaggo/pydoop,crs4/pydoop,simleo/pydoop,simleo/pydoop,simleo/pydoop,elzaggo/pydoop,crs4/pydoop,simleo/pydoop,simleo/pydoop