package main

import (
	"runtime/pprof"
	"context"
	"fmt"
	"time"
)

func main() {
	type favContextKey string

	f := func(ctx context.Context, k string) {
		ctx2 := context.WithValue(context.Background(), "language", "Go2")
		if v := ctx2.Value(k); v != nil {
			fmt.Println("found value:", v)
		} else {
			fmt.Println("key not found:", k)
		}
		pprof.SetGoroutineLabels(ctx)

		if v := ctx.Value(k); v != nil {
			fmt.Println("found value:", v)
		} else {
			fmt.Println("key not found:", k)
		}
	}

	ctx := context.WithValue(context.Background(), "language", "Go")

	f(ctx, "language")
	f(ctx, "color")

	go f(ctx, "language")
	go f(ctx, "color")

	time.Sleep(time.Duration(1) * time.Second)
}