import { MutableRefObject } from "react";
export declare class FontLoader {
    private static counter;
    private static initialized;
    private static ready;
    private static requests;
    static get id(): string;
    private static init;
    private static load;
    private static done;
    static request(
        id: MutableRefObject<string>,
        ref: MutableRefObject<string>,
        context: MutableRefObject<HTMLIFrameElement> | undefined,
        set: MutableRefObject<(family: string) => void>,
        fallback?: string
    ): void;
    static isStandardFont(font: string): boolean;
}