/**
 * @license
 * Copyright 2017 Google LLC
 *
 * 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 { StatsCollection } from './StatsCollection';
/**
 * Returns the delta from the previous call to get stats.
 *
 * @param collection_ - The collection to "listen" to.
 */
export declare class StatsListener {
    private collection_;
    private last_;
    constructor(collection_: StatsCollection);
    get(): {
        [k: string]: number;
    };
}