/**
 * Determine if the request should be retried for the given status code.
 * The below expression reads that we should only retry for:
 *      - HttpStatusCodes that are smaller than 300.
 *      - HttpStatusCodes greater or equal to 500 (except for 501-NotImplement
 *        and 505-HttpVersionNotSupport).
 *      - HttpStatusCode 408-RequestTimeout.
 *      - HttpStatusCode 429.
 * This is based on Microsoft.WindowsAzure.Storage.RetryPolicies.ExponentialRetry class
 * @param httpStatusCode - The status code returned for the request.
 * @returns True if request should be retried, false otherwise.
 */
export declare function retryPolicyShouldRetryForStatus(httpStatusCode: number): boolean;
/**
 * Gets the number of milliseconds to back off before retrying the request. The
 * back off duration is exponentially scaled based on the number of retries already
 * done for the request.
 * @param retriesSoFar - The number of times the request has already been retried.
 * @returns The back off duration for the request before it can be retried.
 */
export declare function retryPolicyGetMillisToBackoffForRetry(retriesSoFar: number): number;