curl --request POST \
  --url https://app.flowglad.com/api/v1/usage-meters \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '{
  "usageMeter": {
    "name": "<string>",
    "pricingModelId": "<string>",
    "slug": "<string>",
    "aggregationType": "sum"
  },
  "price": {
    "type": "single_payment",
    "unitPrice": 123,
    "usageEventsPerUnit": 123
  }
}'

{
  "usageMeter": {
    "id": "<string>",
    "createdAt": 0,
    "updatedAt": 0,
    "livemode": true,
    "organizationId": "<string>",
    "name": "<string>",
    "pricingModelId": "<string>",
    "slug": "<string>",
    "aggregationType": "sum"
  }
}