export declare class DateTimeRef {
    private readonly instant;
    constructor(instant: Date);
    static now(): DateTimeRef;
    toUnixSeconds(): number;
    minusMillisecondsAsIso(offsetMs: number): string;
    plusMillisecondsAsIso(offsetMs: number): string;
    wsaaTraUniqueIdSeconds(): number;
    wsaaTraGenerationTimeIso(): string;
    wsaaTraExpirationTimeIso(): string;
}