delta property
Delta is the change in score from the previous run for this model, absent on the first. It is the number the whole surface exists to make visible.
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
num? delta;