SquareDash/Library/PackageCache/com.unity.purchasing@4.10.0/Documentation~/UnityIAPIStoreInitialization.md

Initialization

Your store’s Initialize method is called by Unity IAP with an IStoreCallback that your store uses to communicate back to Unity IAP asynchronously.

void Initialize(IStoreCallback callback) {
    // Keep a reference to the callback for communicating with Unity IAP.
    this.callback = callback;
}