[Boost-users] [iostreams] Why does boost::iostreams::copy close the Sink & Source?

What's the rationale behind this decision? I don't find it intuitive and reduces the utility of the function. In my case I read from a file into a stream which I want to later use, the signature of the device is important. But as soon as I've copied my data over to the device it's destroyed and along side the data goes down the drain. Kind regards, Sebastian Karlsson