Run a transfer to watch the saga hold, post, and settle — each step appends its event to the log on the left.
Parked — the source was debited but the destination was never credited. Resolve it:
Fund a source for exactly one payment, then fire two transfers at the same instant. Optimistic concurrency on the event log lets one settle and rejects the other for insufficient funds — the source is debited once, never twice.
Balances appear once you seed accounts.
log head#0
events seen0
Balances are a projection rebuilt from the log; the outbox relay tails the same positions to publish events downstream. Both derive from the one ordered source of truth on the left.