Writing archive

I took one small type, Human = man or woman, and compiled it in TypeScript, Rust, and C to see what stays of it. A type is a set of allowed values plus a set of allowed operations, both checked once, and neither reaches the processor.

I started from a small tokio service and hit five classic async Rust problems: a huge future, a future that is not Send, one blocking call that stalls everything, a select! loop that loses data, and a shutdown that hangs. One small model of the compiler and the runtime explains all five.

A decision and failure matrix for combining low-latency webhooks with polling and reconciliation so an integration can recover from missed, duplicate, or reordered events.

A reference flow for keeping user identity, tenant, audience, and allowed actions attached to every AI tool call without trusting the model to enforce permissions.

The usual Fn(&T) -> Fut bound cannot describe a future borrowing from each call. See how AsyncFn enables lending callbacks on stable Rust.