Core Features:

• Implement Tunneler interface for extensibility
• Thread-safe operations with sync.RWMutex
• Graceful shutdown via context cancellation
• Simple HTTP reverse proxy for local development

Testing:

• 12 comprehensive unit tests
• Test lifecycle (start, ready, close)
• Test thread-safe concurrent access
• Test context cancellation
• Test proxy handler with mock server
• Test error handling edge cases
• 86.0% coverage for manager package

Technical Details:

• Proper resource cleanup on shutdown
• Early context cancellation detection
• Idiomatic Go patterns throughout
• Well-documented code with clear comments
• Production-ready error handling