Copying issue with GetStream EnrichedActivity class

I m trying to implement the Copy protocol on swift so that I can copy the activity. But EnrichedActivity has a property originFeedId that is let. And designated initialiser does not take originFeedId parameter.Below is the code for EnrichedActivity initialiser in getStream iOS Pod.

    public init(actor: ActorType,
            verb: Verb,
            object: ObjectType,
            foreignId: String? = nil,
            time: Date? = nil,
            feedIds: FeedIds? = nil) {
    self.actor = actor
    self.verb = verb
    self.object = object
    self.foreignId = foreignId
    self.time = time
    self.feedIds = feedIds
    originFeedId = nil
}