Records one payment against an order, the whole balance or a part of it. While the order's bill is split equally (a payment sent equalSplit), refused with CONFLICT splitWaysMismatch for a part under another number of people, equalSlotClaimed for a part already paid or being paid, splitModeMismatch for a partial payment without equalSplit, and equalSplitUnavailable when a guest split held from the QR menu rules Split equally out. A By items part (a payment sent claimedItems) is refused with BAD_REQUEST itemNotOnBill for a line not on the order, and CONFLICT itemAlreadyClaimed for a quantity already paid or being paid, itemsShareChanged for an amount other than the lines' share, and itemsSplitUnavailable while the bill is split another way; a partial payment without claimedItems, an equal part included, is refused splitModeMismatch while items are claimed. A payment of the whole balance is never refused for the split. An optional tipCents rides beside amountCents, never inside it: it covers nothing on the bill, cash must cover both, and it is refused with BAD_REQUEST tipsOff where the venue's POS tips are off.