public BillingUsage billingUsage(@NotNull LocalDate starDate, @NotNull LocalDate endDate) {
        Single<BillingUsage> billingUsage = api.billingUsage(starDate, endDate);
        return billingUsage.blockingGet();
    }
Account API consumption amount information inquiry.
Up to 100 days of inquiry.

@param starDate
@param endDate
@return Consumption amount information.
service/src/main/java/com/theokanning/openai/service/OpenAiService.java