I am trying to build a custom module that will trigger off a text message when Magento receives shipping information on orders.
I know I can trigger off email, sms etc when an order is placed by listening for the event 'order' referring to this line
$this->_eventManager->dispatch('sales_order_place_after', ['order' => $this]);
In this php file
Magento/Sales/Model/Order.php
So my question is where can I find the event that triggers the default email that gets send when a shipment is generated in Magento2?