Handle BW drop in ALR region and initiate probing

webrtc/modules/pacing/paced_sender.h

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 102 matching lines @@
 
   // Returns the time since the oldest queued packet was enqueued.
   virtual int64_t QueueInMs() const;
 
   virtual size_t QueueSizePackets() const;
 
   // Returns the number of milliseconds it will take to send the current
   // packets in the queue, given the current size and bitrate, ignoring prio.
   virtual int64_t ExpectedQueueTimeMs() const;
 
+  // Application Limited Region refers to operating in a state where the
+  // traffic on network is limited due to application not having enough
+  // traffic to meet the current channel capacity.
+  //
+  // Returns true if network is currently application-limited.
+  bool InApplicationLimitedRegion() const;
+
   // Returns the average time since being enqueued, in milliseconds, for all
   // packets currently in the pacer queue, or 0 if queue is empty.
   virtual int64_t AverageQueueTimeMs();
 
   // Returns the number of milliseconds until the module want a worker thread
   // to call Process.
   int64_t TimeUntilNextProcess() override;
 
   // Process any pending packets in the queue(s).
   void Process() override;
@@ skipping 34 matching lines @@
   uint32_t max_padding_bitrate_kbps_ GUARDED_BY(critsect_);
   uint32_t pacing_bitrate_kbps_ GUARDED_BY(critsect_);
 
   int64_t time_last_update_us_ GUARDED_BY(critsect_);
 
   std::unique_ptr<paced_sender::PacketQueue> packets_ GUARDED_BY(critsect_);
   uint64_t packet_counter_;
 };
 }  // namespace webrtc
 #endif  // WEBRTC_MODULES_PACING_PACED_SENDER_H_