duplicate property
Duplicate is how many members this plane already held. A redelivery collides on its content address and is counted here, not refused: it is the success a retrying caller depends on.
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? duplicate;