@type t() :: %PolarExpress.Schemas.OrderPaidMetadata{
  amount: integer() | nil,
  applied_balance_amount: integer() | nil,
  billing_type: String.t() | nil,
  currency: String.t() | nil,
  discount_amount: integer() | nil,
  discount_id: String.t() | nil,
  net_amount: integer() | nil,
  order_id: String.t() | nil,
  platform_fee: integer() | nil,
  product_id: String.t() | nil,
  recurring_interval: String.t() | nil,
  recurring_interval_count: integer() | nil,
  subscription_id: String.t() | nil,
  tax_amount: integer() | nil
}