introduce interface for data fetching #24
Description
In order to use this library in our application we would need a way to fetch data from a remote.
I like the way you patched it here, which means that it should be relatively easy to do
I would like to propose some kind of interface that a user will be able to pass to the instance of a demuxer, so when we call load or any other function it will use that interface to fetch the data. Caching can also be implemented into the interface as well