Dart's concurrency model is unusual: single-threaded event loop by default, with explicit Isolates for true parallelism. No shared memory, no race conditions, no mutex locks. This guide covers everything from the simple compute() helper to long-lived Isolate workers, structured concurrency patterns, and Stream-based reactive flows. The Mental Model: Isolates vs Threads Concept Dart Isolates JavaScript Workers Java Threads Memory sharing No — message passing only No Yes (with sync overhead) Startup cost ~1-5ms ~1ms ~0.1ms Communication SendPort/ReceivePort postMessage Shared memory Good for CPU-heavy tasks Background compute I/O + CPU mix Dart's lack of shared memory is a feature: it makes concurrent code dramatically safer by eliminating data races entirely.…