我正在尝试在某个函数执行时向某个用户发送推送通知！我发现IOS不支持Firebase云消息传递，所以我切换到expo-notifications，我也看过教程，但它们都需要后端服务器来发送这些通知！我使用Firebase作为我的后端（Firebase Firestore）！所以这可能只适用于Firebase吗？
我想在函数执行时发送通知

const onCancel = async (dateDetails) => {
   setIsSubmitting(true);
   if (!dateDetails.accepted) {
     await deleteDoc(doc(db, "Dates", dateDetails.dateId)).then(() => {
       setIsSubmitting(false);
       Toast.show({
         topOffset: 60,
         type: "success",
         text1: "Date Deleted Successfully",
         text2: " ",
       });
     });
     fetchMyDates().then((res) => {
       setNewDatesOnChild(res);
     });
     //Show a toast
   } else {
     setIsSubmitting(false);
     Alert.alert(
       "Your order has already been accepted Please call this number to Cancel your order !"
     );
   }
 };

如果有其他发送推送通知的方式，请告诉我