Break a bank. Watch the switch cope.

AuthSwitch routes card authorizations to issuing banks. When a bank stops answering, it trips a circuit breaker, approves small purchases on the bank's behalf, and replays them when the bank returns. Everything here is simulated.

Try this

1. Set BANK_A to Down, then send 100 transactions to BANK_A. The breaker opens after 5 failures and the rest are approved by stand-in, within limits.
2. Send to BANK_B. It keeps going, because each bank has its own breaker.
3. Set BANK_A back to Healthy. After the 5-second cool-down, send one transaction. That probe closes the breaker and the queued advices are replayed.
4. Use the 64-at-once button: one message sent 64 times reaches the bank once.