impl Schema for DateTime {
    const SCHEMA: &'static NamedType = &NamedType {
        name: "DateTime",
        ty: &SdmTy::Tuple(&[
            &NamedType {
                name: "year",
                ty: &SdmTy::Varint(Varint::I32),
            },
            &NamedType {
                name: "ordinal",
                ty: &SdmTy::Varint(Varint::U16),
            },
            &NamedType {
                name: "hour",
                ty: &SdmTy::U8,
            },
            &NamedType {
                name: "minute",
                ty: &SdmTy::U8,
            },
            &NamedType {
                name: "second",
                ty: &SdmTy::U8,
            },
            &NamedType {
                name: "nanosecond",
                ty: &SdmTy::Varint(Varint::U32),
            },
            &NamedType {
                name: "offset_hours",
                ty: &SdmTy::I8,
            },
            &NamedType {
                name: "offset_minutes",
                ty: &SdmTy::I8,
            },
            &NamedType {
                name: "offset_seconds",
                ty: &SdmTy::I8,
            },
        ]),
    };
}