Replace all file or directory read/write with abstract resource read/write (do this after milestone "Decouple to interfaces.") We need something like streams or buffers for reading data (input) and writing data (output), and names or ids for what we have debatched (also output). We'll also need an example of a file system implementation that uses our API: a separate console (command-line) debatcher application. The app would know about directories and filesystems, but our core debatcher API would not. Additional useful apps could include a RESTful web service or a datastore adapter to a relational database.