QuickBooks APIs support requestid for idempotent write ops
Docs:

• https://developer.intuit.com/app/developer/qbo/docs/learn/learn-basic-field-definitions#request-id
• https://help.developer.intuit.com/s/article/What-is-RequestId-and-its-usage

Proposal

• New DataService::setRequestId(string $id): self
• Append only for Add, Update, Void, SendEmail
• After each write, requestid is reset (opt-in per call, prevents accidental reuse)
• Backwards-compatible

Example

use QuickBooksOnline\API\DataService\DataService;

$dataService = DataService::Configure($ops);
$result = $dataService->setRequestId('uuid-1234')->Add($invoice);