partial void StartCallClick(NSObject sender)
{
    if (string.IsNullOrWhiteSpace(channelNameTextField.Text))
    {
        channelName.Text = "Please input channel name to proceed";
    }
    else
    {
        var storyboard = UIStoryboard.FromName("Main", null);
        var controller = storyboard.InstantiateViewController("VideoCallView");
        VideoCallViewController.Channel = channelNameTextField.Text;
        this.ShowViewController(controller, this);
    }
}