DateConverter converts a java util Date to an instant or partial.
The Date is converted to milliseconds in the ISO chronology.
author: Stephen Colebourne since: 1.0
Gets the millis, which is the Date millis value.
Parameters: object - the Date to convert, must not be null Parameters: chrono - the non-null result of getChronology the millisecond value throws: NullPointerException - if the object is null throws: ClassCastException - if the object is an invalid type