/**
 * @license
 * Copyright 2018 Palantir Technologies, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import { FetchFunction } from "./fetchBridge";
/**
 * A backoff strategy must return either the number of milliseconds to wait before retrying
 * a request, or undefined to indicate we should stop backing-off (e.g. if the maximum number
 * of retries have been exceeded.
 */
export type BackoffStrategy = (attempt: number) => number | undefined;
/**
 * Implements "exponential backoff with full jitter", suggesting a backoff duration chosen randomly from the interval
 * `[0, backoffSlotSize * 2^c)` for the c-th retry for a maximum of `maxNumRetries` retries.
 */
export declare function exponentialBackoff(maxNumRetries: number, backoffSlotSizeMs: number): BackoffStrategy;
export declare class RetryingFetch {
    private delegate;
    private backoffStrategy;
    constructor(delegate: FetchFunction, backoffStrategy: BackoffStrategy);
    get fetch(): FetchFunction;
    private fetchInternal;
    private getRetryAfterHeaderValueInMilliseconds;
    private getRetryAfter;
    private doAttempt;
}