trying in vain to figure out which goroutine I'm in

Signed-off-by: Jeff Carr <jcarr@wit.com>

example-pprof-simple/Makefile

@@ -1,9 +1,6 @@
 run:
 	GO111MODULE="off" go run -v -x main.go
-
-prep:
-	GO111MODULE="off" go get -v .
-
-build:
-	GO111MODULE="off" go build -v -x
-	# go build
+	@echo
+	@echo "Run foo.go:"
+	@echo
+	GO111MODULE="off" go run foo.go

example-pprof-simple/foo.go

@@ -0,0 +1,38 @@
+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)
+}