An input port on a Dataflow contains a nested output port within it. This
internal output port is used when connecting an edge from the workflow input
to a processor or workflow output (which in turn has a nested input port).
The workflow ports are therefore effectively pairs of ports with a relay
mechanism between the external and internal in the case of the dataflow
Return the internal output port. Output ports have a granular depth
property denoting the finest grained output token they can possibly
produce, this is used to configure downstream filtering input ports. In
this case the finest depth item is determined by the input to the
workflow port and must be explicitly set.
the internal output port
Define the finest grained item that will be sent to this input port. As
all data are relayed through to the internal output port this is used to
denote output port granularity as well as to configure any downstream
connected filtering input ports.