Concurrency

When to reach for a blocking std::sync::Mutex in async code and when you must use tokio's version

Acquire, release, relaxed, sequential consistency — I finally have an intuition for when to use which

Self-referential futures, what they imply for memory layout, and why Pin is not as scary as the type signature suggests

It solves one problem cleanly and creates two others that don't show up until you're at scale

A team I consulted with had stuffed request-scoped configuration into context values and it was slowly eating their tail latencies

sync.Map looks like a drop-in replacement for a map with a mutex, but for most workloads it's slower and harder to reason about

A slow creep in our billing service's memory graph turned out to be goroutines blocked on a channel nobody was draining