It’s very hard to know what’s going on inside privately-owned Stripe. But from the outside, things have not been looking good. The fintech industry has tanked. Cash-hungry companies have tanked. Growth companies have tanked.  Stripe’s closest peer is probably Adyen, a Dutch payments processor. Adyen leans a bit more Europe and a bit more point-of-sale, but it’s not a bad match in its size and product mix.  Adyen is a public company so we can see exactly what the market thinks of it. Its shares have fallen 44 per cent from their peak in October of last year. Another straw…