progress property
Progress is how far along this run is — a share of its goal, a phase, and a line saying what it is doing. Always present, so a board never branches on whether it is there; phase says "unknown" when nothing has estimated it. It is a MODEL ESTIMATE wherever estimated is true, and the row's own word where it is false. See progress.go.
Please note: This property should have been non-nullable! Since the specification file does not include a default value (using the "default:" property), however, the generated source code must fall back to having a nullable type. Consider adding a "default:" property in the specification file to hide this note.
Implementation
SessionProgress? progress;