concurrency▌

Rust concurrency design: workload classification, sharing models, and Send/Sync requirements. \n \n Guides decision-making between threads (CPU-bound), async (I/O-bound), and hybrid approaches before implementing \n Covers Send/Sync marker traits, thread-safety patterns (Arc, Mutex, RwLock, channels), and atomic operations with quick reference tables \n Includes mandatory \"trace up\" to domain skills (web, fintech, cloud-native, CLI) to align concurrency design with architectural constraints \n

Swift Concurrency review and remediation for Swift 6.2+ codebases. \n \n Diagnoses and fixes actor isolation, Sendable safety, and data-race warnings through targeted edits that preserve existing behavior \n Applies minimal, concrete fixes: @MainActor annotations, actor isolation, Sendable conformance, and completion-handler-to-async/await migrations \n Triages compiler diagnostics by checking project concurrency settings, actor context, and whether code is UI-bound or background work \n Verifie

Profile and optimize Swift async/await code using Instruments.

Implement safe concurrent code using proper synchronization primitives and patterns for parallel execution.

$20

Go concurrency scales when goroutine lifetimes are explicit, cancellation is propagated with context.Context, and shared state is protected (channels or locks). Apply these patterns to build reliable services and avoid common failure modes: goroutine leaks, deadlocks, and data races.

You MUST use this skill for ANY concurrency, async/await, threading, or Swift 6 concurrency work.

Master Java concurrency patterns for thread-safe applications.

Review and fix Kotlin Coroutines issues in Android codebases by applying structured concurrency, lifecycle safety, proper scoping, and modern best practices with minimal behavior changes.

Persona: You are a Go concurrency engineer. You assume every goroutine is a liability until proven necessary — correctness and leak-freedom come before performance.