axiom-networking-migration

# Network Framework Migration Guides

## Migration 1: From BSD Sockets to NWConnection

### Migration mapping

| BSD Sockets | NWConnection | Notes |
|-------------|--------------|-------|
| `socket() + connect()` | `NWConnection(host:port:using:) + start()` | Non-blocking by default |
| `send() / sendto()` | `connection.send(content:completion:)` | Async, returns immediately |
| `recv() / recvfrom()` | `connection.receive(minimumIncompleteLength:maximumLength:completion:)` | Async, returns immediately |
| `bind() + listen()` | `NWListener(using:on:)` | Automatic port binding |
| `accept()` | `listener.newConnectionHandler` | Callback for each connection |
| `getaddrinfo()` | Let NWConnection handle DNS | Smart resolution with racing |
| `SCNetworkReachability` | `connection.stateUpdateHandler` waiting state | No race conditions |
| `setsockopt()` | `NWParameters` configuration | Type-safe options |

### Example migration

#### Before (BSD Sockets)
```c
// BEFORE — Blocking, manual DNS, error-prone
var hints = addrinfo()
hints.ai_family = AF_INET
hints.ai_socktype = SOCK_STREAM

var results: UnsafeMutablePointer<addrinfo>?
getaddrinfo("example.com", "443", &hints, &results)

let sock = socket(results.pointee.ai_family, results.pointee.ai_socktype, 0)
connect(sock, results.pointee.ai_addr, results.pointee.ai_addrlen) // BLOCKS

let data = "Hello".data(using: .utf8)!
data.withUnsafeBytes { ptr in
    send(sock, ptr.baseAddress, data.count, 0)
}
```

#### After (NWConnection)
```swift
// AFTER — Non-blocking, automatic DNS, type-safe
let connection = NWConnection(
    host: NWEndpoint.Host("example.com"),
    port: NWEndpoint.Port(integerLiteral: 443),
    using: .tls
)

connection.stateUpdateHandler = { state in
    if case .ready = state {
        let data = Data("Hello".utf8)
        connection.send(content: data, completion: .contentProcessed { error in
            if let error = error {
                print("Send failed: \(error)")
            }
        })
    }