content: /*
   * Copyright (C) 2021 The Android Open Source Project
   *
   * 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.
   */
  package com.google.android.exoplayer2.upstream;
  
  import com.google.android.exoplayer2.C;
  
  /** Provides an estimate of the time to first byte of a transfer. */
  public interface TimeToFirstByteEstimator {
    /**
     * Returns the estimated time to first byte of the response body, in microseconds, or {@link
     * C#TIME_UNSET} if no estimate is available.
     */
    long getTimeToFirstByteEstimateUs();
  
    /** Resets the estimator. */
    void reset();
  
    /**
     * Called when a transfer is being initialized.
     *
     * @param dataSpec Describes the data for which the transfer is initialized.
     */
    void onTransferInitializing(DataSpec dataSpec);
  
    /**
     * Called when a transfer starts.
     *
     * @param dataSpec Describes the data being transferred.
     */
    void onTransferStart(DataSpec dataSpec);
  }
  