e C<Accept> header, this resource will either return
RDFa-embedded (X)HTML, RDF/XML or Turtle (or JSON-LD, or whatever).
The HTML version includes a rudimentary interface to the
C<multipart/form-data>
TODO>: find or make an appropriate collection vocab, then implement
RDFa, RDF/XML, N3/Turtle, and JSON-LD variants.
=cut
$DISPATCH{partial}{GET} = sub {
# we need (maybe) algo, non-zero partial