Check if user installed my app from Snapchat using AppsFlyer SDK

Question

I'm using AppsFlyer and trying to set up ads in Snapchat. When users install the app from Snapchat I see a separate column of users in AppsFlyer for "media_source – snapchat_int". I want to determine if the user came from Snapchat on app launch. I tried doing this:

func onConversionDataSuccess(_ data: [AnyHashable: Any]) {
    if let source = data["media_source"] as? String {
      if source == "snapchat_int" {
        print("This is a user from Snapchat")
        //Do other snapchat things
      }
    }
}

But source is always nil. AppsFlyer somehow knows that this is an install from Snapchat, I just can't figure out where is this data passed and how to intercept it.

P.S. AppsFlyer account info is not present in my Snapchat ads manager, and I'm not using OneLink (I don't think it's possible), just inserting the appID in the Snapchat Ad.