Notification submission does not recognize attribute time_to_live (TTL) in cURL with Firebase

Hi, I have a problem with notifications sent through Firebase , the notification is sent perfectly, but by setting the time_to_live (TTL) attribute or message life time it does not recognize it, just overlooked and does not take it into account

curl -X POST -H "Authorization: key=<KEY-API>" -H  Content-Type: 
application/json" -d 
"{\"webpush\":{
     \"headers\":{
        \"TTL\":\"5s\"}
        },
  \"to\": \"<TOKEN>\", 
     \"notification\": { 
        \"title\": \"Clase\", 
        \"body\": \"Tienes una clase en vivo en 5 minutos.\", 
        \"icon\": \"/firebase-logo.png\"}}" "https://fcm.googleapis.com/fcm/send"

What is wanted is that when a notification is sent and the browser is closed for more than a certain time (TLL), the notification does not reach its destination and I understand according to the documentation that the TLL applies for that case

the cURL is written in this way by the use of windows CMD for sending test notifications