/// <summary> /// Converts a single Facebook messenger message to a Bot Framework activity. /// </summary> /// <param name="message">The message to be processed.</param> /// <returns>An Activity with the result.</returns> /// <exception cref="ArgumentNullException"><paramref name="message"/> is null.</exception> /// <remarks>A webhook call may deliver more than one message at a time.</remarks> public static Activity ProcessSingleMessage(FacebookMessage message) { if (message == null) { throw new ArgumentNullException(nameof(message)); } if (message.Sender == null && message.OptIn?.UserRef != null) { message.Sender = new FacebookBotUser { Id = message.OptIn?.UserRef }; } var activity = new Activity() { ChannelId = "facebook", Timestamp = default,