PayPal - 发送发票时如何检测/触发webhook?

In PayPal, there are invoice webhook if it's paid, created, updated etc. but how can I detect if the invoice is sent?

The app will create an invoice as DRAFT, then the merchant will go to PayPal's invoice page (maybe to modify the invoice or not) and manually send the invoice. I thought it will be triggered in updated webhook because the status will be changed, but it didn't.

Is there any event that paypal will emit if the invoice is sent? Does it have another workaround if I can't use webhook?