otelhttptrace-wait100.go

package main

import (
	"bytes"
	"context"
	"fmt"
	"io"
	"log"
	"net/http"
	"net/http/httptest"
	"net/http/httptrace"

	"go.opentelemetry.io/contrib/instrumentation/net/http/httptrace/otelhttptrace"
)

func main() {
	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		fmt.Fprintln(w, "Hello, client")
	}))
	defer ts.Close()

	clientTrace := otelhttptrace.NewClientTrace(context.Background())
	ctx := httptrace.WithClientTrace(context.Background(), clientTrace)

	req, _ := http.NewRequestWithContext(ctx, "POST", ts.URL, bytes.NewReader([]byte("test")))
	req.Header.Set("Expect", "100-continue")

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		log.Fatal(err)
	}
	io.Copy(io.Discard, res.Body)
	res.Body.Close()
	log.Printf("%v", res)
}