SYSML17 — Suggest capability to list :features on ItemFlows in a rectangle symbol over a Connector or Association line

This ticket is a re-imagining of (partial resurrection of) a proposal from Michael Chonoles that I strongly supported:

https://issues.omg.org/browse/SYSML17-103

https://issues.omg.org/browse/SYSML17-208

If the RTF chairs truly consider any new features out-of-scope this can be bumped to SysMLv2, but as Conrad wrote under SYSML17-208:

I think SysML 1.x should address this. It will be a long time before SysML2 is a finalized OMG spec. We should be supporting modelers in the meantime with small upgrades like this.

SysML already has the capability to list :features (such as :values, :operations etc.) in compartments on Property and Port symbols in IBDs. Indeed, this notation has proved one of the most popular advantages of SysML over UML.

The same capability could be introduced for ItemFlows, which could be extended to optionally support representation as a rectangle symbol on Connectors lines and Associations lines (or wherever ItemFlows may be shown), with compartments for listing :features.

In the case where the ItemFlow does not have an itemProperty, the rectangle could appear much like a Block symbol (but over a relevant line).

In the case where the ItemFlow has an itemProperty, the rectangle could appear much like a Property symbol (but over a relevant line).

In both cases the header of the rectangle could show the direction arrow for the ItemFlow.

In both cases the ability to display defaults for value properties would be extremely useful.

(Variations on the notation would have to cope with situations where there is more than one applied ItemFlow.)