Function buildFalUsage

packages/ai-fal/src/utils/billing.ts:81–91

(
  unitsBilled: number | undefined,
)

 * callers can omit `usage` entirely.
 */
export function buildFalUsage(
  unitsBilled: number | undefined,
): TokenUsage | undefined {
  if (unitsBilled == null) return undefined
  return {
    promptTokens: 0,
    completionTokens: 0,
    totalTokens: 0,
    unitsBilled,
  }
}

/**
 * Wrap a fetch so every fal request's response is inspected for the