FedEx is preparing for a “surge volume” event from Sept. 21-24—a period that coincides with persistent rumors of a Sept. 21 iPhone launch—according to a FedEx notice spotted by MacRumors. Neither Apple nor the new iPhone are mentioned by name within the short internal FedEx communication, which alludes to a postponement of employee training during the “surge;” however, FedEx is one of Apple’s primary shipping…