Adds the user-resettable advertising identifier (IDFA) to each tracking call and optionally implements the Apple Search Ads API to gather attribution information (see [[external] Apple Search Ads](https://searchads.apple.com/help/pdf/attribution-api.pdf for details)).
Foundation, UIKit, AdSupport, iAd
Usage of this module is optional. Please take the time to read about its functionality and decide if you really need it, as it introduces additional dependencies. Additionally, you will be required to explain to Apple why you are using IDFA when you submit your app. It should suffice to say that you are using it for attribution purposes. If you do not state that you are using IDFA, Apple will reject your app (see [external]: IDFA Usage).
If you choose to disable the module, the variables listed below will not be included in tracking calls.
The following variables will be transmitted with each tracking call while the module is enabled:
|Variable Name||Description||Example Value|
|device_advertising_id||User-resettable advertising identifier (IDFA)||6D92078A-8246-4BA4-AE5B-76104861E7DC|
|device_advertising_vendor_id||Unique ID guaranteed to be the same across all apps on the same device from a single vendor (apps with the same 1st 2 parts of the RDNS bundle identifier e.g. com.tealium or com.acme)||6D92078A-8246-4BA4-AE5B-76104861E7DC|
|device_advertising_enabled||Boolean to indicate whether the user has allowed ad tracking. True if ad tracking enabled, otherwise false. Note: if false, the advertising ID will appear as a string of zeroes||true|
|ad_user_clicked_last_30_days*||True if user clicked on a Search Ads impression within 30 days prior to app download.||true|
|ad_user_date_clicked*||Date and time the user clicked on a corresponding ad||2016-12-05T17:31:40Z|
|ad_user_date_converted*||Date and time the user downloaded your app||2016-12-05T17:31:40Z|
|ad_org_name*||The organization that owns the campaign the corresponding ad was part of.||OrgName|
|ad_campaign_id*||The ID of the campaign the corresponding ad was part of||1234567890|
|ad_campaign_name*||The name of the campaign the corresponding ad was part of||CampaignName|
|ad_group_id*||The ID of the ad group the corresponding ad was part of||1234567890|
|ad_group_name*||The name of the ad group the corresponding ad was part of.||AdGroupName|
|ad_keyword*||The keyword that drove the ad impression which led to the corresponding ad click.||Keyword|
* Note: these variables are only enabled if Search Ads has been explicitly enabled in the TealiumConfig object. These variables will only be retrieved from Apple's servers once during the app's lifetime, but they will be stored as persistent variables so they are available on future app launches.
Update IDFA functionality to have a more robust retry mechanism if IDFA retrieval fails the first time (documented Apple limitation).