New feature: Support for Partial Payments in Connect v1
The Connect SDK now supports partial payment functionality for the Connect v1 Transactions API with the addition of a new `Payment` field:
* `Payment.is_partial` — Indicates whether or not the payment is only partially paid for. If `true`, the payment will have the tenders collected so far, but the itemizations will be empty until the payment is completed.
`Tender` also includes 2 new fields to help resolve timing around payments with multiple tenders. Invoices that involve partial payment (e.g., requiring a deposit) may include tenders settled well before the entire payment is completed:
* `Tender.tendered_at` — The time when the tender was accepted by the merchant.
* `Tender.settled_at` — The time when the tender was captured, in ISO 8601 format. Typically the same as (or within moments of) `tendered_at` unless the tender was part of a delay capture transaction.
The change also makes some behavioral changes to the Connect v1 Payment endpoints:
* **Create Refunds** rejects requests for invoices that have partial payments pending.
* **List Payments** takes a new request field, `include_partial` to indicate whether partial payments should be included in the response.