Wrong implemention of didObserveICEConnectionStateChange

[oney]

When state is RTCICEConnectionClosed in didObserveICEConnectionStateChange, peerID is nil.

- (void)peerConnection:(RTCPeerConnection *)peerConnection iceConnectionChanged:(RTCICEConnectionState)newState {
    dispatch_async(dispatch_get_main_queue(), ^{
        [self.delegate webRTC:self didObserveICEConnectionStateChange:newState forPeerWithID:[self identifierForPeer:peerConnection]];
    });
}

Because after calling removePeerConnectionForID, RTCPeerConnection will be removed from self.peerConnections, and it is closed. Then, the peerConnection:(RTCPeerConnection *)peerConnection iceConnectionChanged:(RTCICEConnectionState)newState is called, [self identifierForPeer:peerConnection] will always be nil.

- (void)removePeerConnectionForID:(NSString *)identifier {
    RTCPeerConnection* peer = self.peerConnections[identifier];
    [self.peerConnections removeObjectForKey:identifier];
    [self.peerToRoleMap removeObjectForKey:identifier];
    [peer close];
}