This makes the following changes, before:
type backend interface {
// Test a boolean value whether a File with the name and type exists.
Test(t FileType, name string) (bool, error)
// Remove removes a File with type t and name.
Remove(t FileType, name string) error
}
After:
type backend interface {
// Test a boolean value whether a File with the name and type exists.
Test(h Handle) (bool, error)
// Remove removes a File with type t and name.
Remove(h Handle) error
}