public static OffsetDateTime timestampOfEpochMilli(long epochMilli) {
        Instant instant = Instant.ofEpochMilli(epochMilli);
        return OffsetDateTime.ofInstant(instant, ZoneOffset.UTC);
    }
Obtains an instance of OffsetDateTime using milliseconds from the epoch
@param epochMilli the number of milliseconds from epoch
@return the offset date-time, not null
src/main/java/org/replicadb/time/Conversions.java