Count (Json Schema Count Property)
This fixed property defines a named value that increments by one each time the schema generates. You could use this property
for message IDs.
Figure 53. Count property
To add this property to a schema object or array, expand the Properties folder in the palette and drag a Count to the root object { } or to an array [ ] under the root object, then double-click the Count component.
This property is a number that defaults to zero (0).
To return this value to zero, right-click the Count property and click .