curl --request POST \
  --url https://app.flowglad.com/api/v1/usage-events \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "usageEvent": {
    "subscriptionId": "<string>",
    "amount": 123,
    "transactionId": "<string>",
    "usageDate": 0,
    "properties": {},
    "priceId": "<string>",
    "priceSlug": "<string>",
    "usageMeterId": "<string>",
    "usageMeterSlug": "<string>"
  }
}
'

{
  "usageEvent": {
    "id": "<string>",
    "createdAt": 0,
    "updatedAt": 0,
    "livemode": true,
    "customerId": "<string>",
    "subscriptionId": "<string>",
    "usageMeterId": "<string>",
    "amount": 123,
    "usageDate": 0,
    "transactionId": "<string>",
    "priceId": "<string>",
    "pricingModelId": "<string>",
    "billingPeriodId": "<string>",
    "properties": {}
  }
}