When a batch is created and scheduled for processing, you will get the event payload as below:
{
event_type: "batch.started",
resource_type: "shipment_batch",
resource_id: "3ed3d05f-7ba8-404d-97b1-5a50de300001",
batch: {
started_at: "2023-01-25T11:30:00.000Z",
items: 2
}
}