package logging import (	"context"	"net/http"	"testing") func TestWithFreshResponseHeadersHolderIsolatesAttempts(t *testing.T) {	requestCtx := WithResponseHeadersHolder(context.Background())	SetResponseHeaders(requestCtx, http.Header{"X-Upstream-Attempt": []string{"request"}}) 	firstAttemptCtx := WithFreshResponseHeadersHolder(requestCtx)	if headers := GetResponseHeaders(firstAttemptCtx); len(headers) != 0 {		t.Fatalf("fresh attempt inherited request headers: %#v", headers)	}	SetResponseHeaders(firstAttemptCtx, http.Header{"X-Upstream-Attempt": []string{"first"}}) 	secondAttemptCtx := WithFreshResponseHeadersHolder(firstAttemptCtx)	if headers := GetResponseHeaders(secondAttemptCtx); len(headers) != 0 {		t.Fatalf("second attempt inherited first attempt headers: %#v", headers)	}	SetResponseHeaders(secondAttemptCtx, http.Header{"X-Upstream-Attempt": []string{"second"}}) 	if got := GetResponseHeaders(requestCtx).Get("X-Upstream-Attempt"); got != "request" {		t.Fatalf("request holder = %q, want request", got)	}	if got := GetResponseHeaders(firstAttemptCtx).Get("X-Upstream-Attempt"); got != "first" {		t.Fatalf("first attempt holder = %q, want first", got)	}	if got := GetResponseHeaders(secondAttemptCtx).Get("X-Upstream-Attempt"); got != "second" {		t.Fatalf("second attempt holder = %q, want second", got)	}}