failures7d property
Failures7d is how many of those settled as failed — the subscriber never accepted it and no further attempt will be made. It is the numerator to Deliveries7d, over the same window.
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
int? failures7d;