ios-networking

URLSession with async/await lets you handle HTTP requests concurrently without callbacks. Use `URLSession.shared.data(from:)` or `URLSession.data(from:delegate:)` to fetch data, decode responses, and manage errors in a linear, readable flow that integrates with Swift's structured concurrency model.

URLSession handles HTTP/HTTPS requests and higher-level protocols; Network.framework provides lower-level socket control for raw TCP/UDP, custom protocols, and fine-grained connection diagnostics. Choose URLSession for APIs and Network.framework when you need direct socket access or advanced connection monitoring.

TLS and timeout issues stem from certificate validation, protocol mismatches, or network latency. Use Network.framework's connection state monitoring, enable URLSession logging, inspect certificate chains, and verify server configuration. Test with explicit timeout values and retry logic to isolate root causes.

Yes. Replace NSURLConnection with URLSession for HTTP tasks, and adopt Network.framework for socket-level work. Both support modern concurrency patterns. Migration paths include wrapping legacy code temporarily while refactoring incrementally to reduce risk and maintain compatibility.

URLSessionWebSocketTask handles WebSocket protocols natively. For raw sockets, use Network.framework's NWConnection to establish TCP/UDP streams, manage send/receive cycles, and handle connection state changes. Both support async/await for structured concurrency.

Check DNS resolution, TLS certificate validity, timeout thresholds, and connection state transitions. Use Network.framework's pathMonitor for reachability, enable URLSession request/response logging, and inspect error codes to distinguish network unavailability from application logic failures.