datetime
- https://schema.org/DateTime
- https://firebase.google.com/docs/reference/kotlin/com/google/firebase/dataconnect/serializers/KotlinxDatetimeLocalDateSerializer
- https://www.loc.gov/standards/datetime/
- https://www.w3.org/TR/NOTE-datetime
- http://www.w3.org/TR/NOTE-datetime
- https://firebase.google.com/docs/reference/android/com/google/firebase/ml/vision/barcode/FirebaseVisionBarcode.CalendarDateTime