net.http integration example

This example shows how x.async can coordinate local net.http request and response handling without opening a network listener.

It is intentionally synthetic: requests are constructed in memory, processed by a small handler, and drained through a Pool. This keeps the example stable while still showing the lifecycle pattern used by HTTP-facing code:

• construct or receive a http.Request;
• submit bounded work to an x.async.Pool;
• publish a http.Response result;
• close the pool and report the first error if one occurred.

Run from the repository root:

./v run vlib/x/async/examples/net_http/request_batch.v

No external service, fixed port, file path, or real HTTP server is used.