curl --request POST \
  --url https://api.eflow.team/v1/networks/billings/affiliates/invoices \
  --header 'Content-Type: application/json' \
  --header 'X-Eflow-Api-Key: <api-key>' \
  --data '
{
  "network_affiliate_id": 1,
  "status": "unpaid",
  "start_time": "2024-01-01",
  "end_time": "2024-01-31",
  "public_notes": "January earnings",
  "internal_notes": "",
  "is_hidden_affiliate": false,
  "payment_terms": 30
}
'

{
  "network_affiliate_invoice_id": 123,
  "network_id": 123,
  "network_affiliate_id": 123,
  "status": "paid",
  "start_time": "<string>",
  "end_time": "<string>",
  "balance": 123,
  "billed": 123,
  "paid": 123,
  "public_notes": "<string>",
  "internal_notes": "<string>",
  "is_hidden_affiliate": true,
  "payment_terms": 123,
  "time_created": 123,
  "time_saved": 123,
  "relationship": {}
}