/*!
 * Copyright (c) Microsoft Corporation and contributors. All rights reserved.
 * Licensed under the MIT License.
 */
/**
 * A rate limiter to make sure that a client can only request help for one task within a time window.
 *
 * @deprecated This class has no replacement.
 *
 * @privateremarks
 * This class is not used anywhere in the repo. driver-utils already has a similar class that is used by the odsp and
 * routerlicious drivers.
 * @internal
 */
export declare class RateLimiter {
    private readonly windowMSec;
    private readonly requestMap;
    /**
     * Creates a rate limiter that keep track of the request it has made
     *
     * @param windowMSec - time in millisecond, use to filter out messages
     * for a clientId if the last request falls within this time window
     */
    constructor(windowMSec: number);
    /**
     * Filter out the messages that had already been requested within the time window
     *
     * @param clientId - the clientId who want to send the message
     * @param messages - the message we want to send
     * @returns the message we approved to send that hasn't been sent recently
     */
    filter(clientId: string, messages: string[]): string[];
}
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