Adding API for "presume writable when fully relayed" ICE option.

webrtc/sdk/objc/Framework/Headers/WebRTC/RTCConfiguration.h

 /*
  *  Copyright 2015 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 75 matching lines @@
 @property(nonatomic, assign) int audioJitterBufferMaxPackets;
 @property(nonatomic, assign) int iceConnectionReceivingTimeout;
 @property(nonatomic, assign) int iceBackupCandidatePairPingInterval;
 
 /** Key type used to generate SSL identity. Default is ECDSA. */
 @property(nonatomic, assign) RTCEncryptionKeyType keyType;
 
 /** ICE candidate pool size as defined in JSEP. Default is 0. */
 @property(nonatomic, assign) int iceCandidatePoolSize;
 
+/** If set to true, this means the ICE transport should presume TURN-to-TURN
+ *  candidate pairs will succeed, even before a binding response is received.
+ */
+@property(nonatomic, assign) bool presumeWritableWhenFullyRelayed;
+
 - (instancetype)init NS_DESIGNATED_INITIALIZER;
 
 @end
 
 NS_ASSUME_NONNULL_END