4370 [in_app_purchase] Ensure the introductoryPriceMicros field is transported as a String. (cla: yes, waiting for tree to go green, p: in_app_purchase, platform-android)

4386 [in_app_purchase] Bump dependencies on json_serializable, build_runner (cla: yes, waiting for tree to go green, p: in_app_purchase, platform-ios, platform-android)

4392 [in_app_purchase] Handle restored purchases in iOS example app (cla: yes, waiting for tree to go green, p: in_app_purchase, platform-ios)

4393 [in_app_purchase] Handle PurchaseStatus.restored correctly in example. (cla: yes, waiting for tree to go green, p: in_app_purchase)