You are a Principal Software Engineer specializing in distributed real-time systems and WebSocket architecture. Design and implement a complete, production-ready WebSocket service based on the specifications below.

## TECHNICAL SPECIFICATIONS
- **Programming Language**: [PROGRAMMING_LANGUAGE]
- **WebSocket Framework**: [FRAMEWORK] (e.g., Socket.io, ws, FastAPI WebSockets, Gorilla, SocketCluster)
- **Use Case**: [USE_CASE] (e.g., live chat, stock ticker, multiplayer gaming, collaborative editing)
- **Scale Target**: [SCALE_REQUIREMENTS] (e.g., 10k concurrent connections, 1M messages/second)
- **Authentication Method**: [AUTH_METHOD] (e.g., JWT tokens, API keys, OAuth2, session cookies)
- **Persistence Layer**: [PERSISTENCE_REQUIREMENT] (e.g., Redis pub/sub, PostgreSQL message history, none)
- **Infrastructure**: [INFRASTRUCTURE] (e.g., Docker containers, Kubernetes, AWS ECS, bare metal)

## DELIVERABLES (Generate All Sections)

### 1. Architecture Diagram (Text-Based)
Provide an ASCII or markdown representation of the system architecture including load balancers, WebSocket servers, Redis cluster (if applicable), and database connections.

### 2. Project Structure
Show the complete file tree with separation of concerns (handlers, middleware, models, config, tests).

### 3. Core Implementation Code
Generate production-quality code including:
- Server initialization with graceful shutdown handling
- Connection manager with heartbeat/ping-pong mechanisms
- Message protocol schemas (JSON validation)
- Room/namespace management logic
- Event handlers for connect/disconnect/message/error events
- Broadcasting and multicast patterns

### 4. Authentication & Security
Implement:
- Connection upgrade authentication middleware
- CORS configuration for WebSocket origins
- Rate limiting per IP/user
- Input sanitization and message size limits
- Protection against DDoS and connection flooding

### 5. Scaling & High Availability
Detail:
- Horizontal scaling strategy with sticky sessions (or stateless architecture)
- Redis adapter configuration for multi-server synchronization (if applicable)
- Load balancer configuration (nginx/HAProxy/AWS ALB settings for WebSocket support)
- Connection distribution algorithms

### 6. Error Handling & Resilience
Include:
- Automatic reconnection logic with exponential backoff
- Circuit breakers for external service calls
- Memory leak prevention (proper cleanup on disconnect)
- Fallback to long-polling or SSE if WebSocket fails
- Structured logging with correlation IDs

### 7. Database Integration (if applicable)
- Schema for message persistence
- Write strategies (async batching vs immediate)
- Connection pooling configuration

### 8. Monitoring & Observability
- Health check endpoints
- Metrics collection (Prometheus/Grafana compatible)
- Connection count tracking
- Message throughput monitoring
- Error rate alerting

### 9. Testing Strategy
- Unit test examples for event handlers
- Load testing scripts (using Artillery or k6)
- Integration test patterns for WebSocket flows

### 10. Deployment Configuration
- Dockerfile optimized for [PROGRAMMING_LANGUAGE] WebSocket servers
- Docker Compose for local development with dependencies
- Environment variable documentation
- Cloud deployment notes (AWS/GCP/Azure specific gotchas)

## CODE QUALITY REQUIREMENTS
- Use [PROGRAMMING_LANGUAGE] idioms and best practices (async/await, proper typing, error handling)
- Include comprehensive inline comments explaining WebSocket-specific decisions
- Ensure thread-safety and prevent race conditions in connection management
- Optimize for low latency and high throughput
- Follow OWASP security guidelines for real-time applications