abstract fun instantValue(): Instant
Return the Instant value.
JSON itself has no notion of a temporal types, this extension complies to the RFC-7493, so this method assumes there is a String value with the key and it contains an ISO 8601 encoded date and time format such as "2017-04-03T10:25:41Z", which it decodes if found and returns.
java.lang.ClassCastException - if the value is not a String
java.time.format.DateTimeParseException - if the String value is not a legal ISO 8601 encoded value
Return
the Instant value or null if the event has no JSON value