Module exposing an indexed array of typed-function ports.
Instantiates ``num_entries`` ``FuncService`` ports under the same appid name
``call`` with indices 0..N-1 -- the codegen groups them into a single
``IndexedPorts<TypedFunction<...>>`` member, which the C++ driver iterates
over (``connected->call[i]``). Each entry returns ``arg + (i+1)``, so the
driver can verify it talked to the right index by sending the same arg to
every entry and comparing replies.
Definition at line 331 of file test_codegen.py.