csharp-concurrency-patterns

1# .NET Concurrency: Choosing the Right Tool
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3## When to Use This Skill
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5Use this skill when:
6- Deciding how to handle concurrent operations in .NET
7- Evaluating whether to use async/await, Channels, Akka.NET, or other abstractions
8- Tempted to use locks, semaphores, or other synchronization primitives
9- Need to process streams of data with backpressure, batching, or debouncing
10- Managing state across multiple concurrent entities
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12## Reference Files
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14- [advanced-concurrency.md](advanced-concurrency.md): Akka.NET Streams, Reactive Extensions, Akka.NET Actors (entity-per-actor, state machines, cluster sharding), and async local function patterns
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16## The Philosophy
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18**Start simple, escalate only when needed.**
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20Most concurrency problems can be solved with `async/await`. Only reach for more sophisticated tools when you have a specific need that async/await can't address cleanly.
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22**Try to avoid shared mutable state.** The best way to handle concurrency is to design it away. Immutable data, message passing, and isolated state (like actors) eliminate entire categories of bugs.
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24**Locks should be the exception, not the rule.** When you can't avoid shared mutable state:
251. **First choice:** Redesign to avoid it (immutability, message passing, actor isolation)
262. **Second choice:** Use `System.Collections.Concurrent` (ConcurrentDictionary, etc.)
273. **Third choice:** Use `Channel<T>` to serialize access through message passing
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