Ping backup connection at a slower rate

talk/app/webrtc/objc/public/RTCPeerConnectionInterface.h

 /*
  * libjingle
  * Copyright 2015 Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *  1. Redistributions of source code must retain the above copyright notice,
  *     this list of conditions and the following disclaimer.
  *  2. Redistributions in binary form must reproduce the above copyright notice,
@@ skipping 46 matching lines @@
 // Configuration object used for creating a peer connection.
 @interface RTCConfiguration : NSObject
 
 @property(nonatomic, assign) RTCIceTransportsType iceTransportsType;
 @property(nonatomic, copy) NSArray *iceServers;
 @property(nonatomic, assign) RTCBundlePolicy bundlePolicy;
 @property(nonatomic, assign) RTCRtcpMuxPolicy rtcpMuxPolicy;
 @property(nonatomic, assign) RTCTcpCandidatePolicy tcpCandidatePolicy;
 @property(nonatomic, assign) int audioJitterBufferMaxPackets;
 @property(nonatomic, assign) int iceConnectionReceivingTimeout;
+@property(nonatomic, assign) int iceBackupConnectionPingInterval;
 
 - (instancetype)initWithIceTransportsType:(RTCIceTransportsType)iceTransportsType
                              bundlePolicy:(RTCBundlePolicy)bundlePolicy
                             rtcpMuxPolicy:(RTCRtcpMuxPolicy)rtcpMuxPolicy
                        tcpCandidatePolicy:(RTCTcpCandidatePolicy)tcpCandidatePolicy
               audioJitterBufferMaxPackets:(int)audioJitterBufferMaxPackets
-            iceConnectionReceivingTimeout:(int)iceConnectionReceivingTimeout;
+            iceConnectionReceivingTimeout:(int)iceConnectionReceivingTimeout
+          iceBackupConnectionPingInterval:(int)iceBackupConnectionPingInterval;
 
 @end