feat: integration usockets backend

usockets/README.md

@@ -0,0 +1,89 @@
+# uSockets Backend for V-Hono
+
+High-performance server backend using [uSockets](https://github.com/uNetworking/uSockets) library.
+
+## Performance
+
+Based on benchmark tests (200 connections, 100K requests):
+
+| Backend | RPS | Avg Latency | P95 | P99 |
+|---------|-----|-------------|-----|-----|
+| uSockets | ~22,000 | 8.75ms | 16.66ms | 25.73ms |
+| picoev | ~15,000 | 13.36ms | 18.89ms | 31.66ms |
+
+**uSockets provides ~50% higher throughput under high concurrency.**
+
+## Usage
+
+```v
+import hono
+
+fn main() {
+    mut app := hono.Hono.new()
+    
+    app.get('/', fn (mut c hono.Context) http.Response {
+        return c.text('Hello from uSockets!')
+    })
+    
+    // Use uSockets backend
+    app.listen_usockets(3000)
+}
+```
+
+## Build Command
+
+```bash
+v -enable-globals -cc gcc -ldflags "-ldbghelp" your_app.v -o app.exe
+```
+
+**Required flags:**
+- `-enable-globals` - Required for uSockets global state
+- `-cc gcc` - Use GCC compiler (MinGW-w64 on Windows)
+- `-ldflags "-ldbghelp"` - Fix Windows linking (Windows only)
+
+## Prerequisites (Windows)
+
+1. **GCC (MinGW-w64)**
+   ```powershell
+   scoop install mingw
+   # or
+   choco install mingw
+   ```
+
+2. **V Compiler** (0.4.x or later)
+   ```powershell
+   scoop install vlang
+   ```
+
+## Directory Structure
+
+```
+usockets/
+├── include/           # Header files
+│   ├── libusockets.h  # uSockets API
+│   ├── uv.h           # libuv API
+│   └── uv/            # libuv headers
+├── lib/               # Pre-compiled libraries
+│   ├── libusockets_full.a  # uSockets + libuv (main)
+│   ├── libuv.a             # libuv static lib
+│   └── ...
+└── usockets.v         # V bindings
+```
+
+## Configuration
+
+```v
+// Custom configuration
+app.listen_usockets_with_config(hono.UsocketsConfig{
+    port: 8080
+    host: '0.0.0.0'
+    keepalive_timeout: 30
+    max_keepalive_req: 10000
+})
+```
+
+## Notes
+
+- On Windows, uSockets and picoev have similar performance
+- On Linux, uSockets may have greater advantages due to epoll optimization
+- uSockets excels under high concurrency (200+ connections)