This extracts some common API-idiosyncracy-handling patterns from model serialisers into properties that are processed by the application serialiser:
* arrayNullOverrides converts a null property value to an empty array
* mapToArray converts a map to an array of maps, using the original map keys as Name properties on the array maps
* separateNanos splits nanosecond-containing timestamps into millisecond timestamps and separate nanosecond properties
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