Previously the arguments to the operator of a vtkm::cont::arg::Transport
were the control object, the input domain object, and the output range.
If you wanted to, for example, check the size of an input array to make
sure it matched the input range, you would have to know the meaning of
the input domain object to query its range. This made it hard to create
generic transports, like TransportTagArrayIn, that accept data from
multiple different input domains but need to know the input range.