public static DeliveryError ofCode(int code) {
        for (DeliveryError e : DeliveryError.values()) {
            if (e.code == code)
                return e;
        }

        return UNKNOWN;
    }
Returns the appropriate {@code DeliveryError} enum
corresponding to the Apple provided status code

@param code  status code provided by Apple
@return  the appropriate DeliveryError
src/main/java/com/notnoop/apns/DeliveryError.java