Introduce a fast proxy mode to improve HTTP/1.1 performances with backends

Co-authored-by: Romain <rtribotte@users.noreply.github.com>
Co-authored-by: Julien Salleyron <julien.salleyron@gmail.com>

pkg/proxy/httputil/builder_test.go

@@ -0,0 +1,56 @@
+package httputil
+
+import (
+	"crypto/tls"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"github.com/traefik/traefik/v3/pkg/config/dynamic"
+	"github.com/traefik/traefik/v3/pkg/testhelpers"
+)
+
+func TestEscapedPath(t *testing.T) {
+	var gotEscapedPath string
+	srv := httptest.NewServer(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
+		gotEscapedPath = req.URL.EscapedPath()
+	}))
+
+	transportManager := &transportManagerMock{
+		roundTrippers: map[string]http.RoundTripper{"default": &http.Transport{}},
+	}
+
+	p, err := NewProxyBuilder(transportManager, nil).Build("default", testhelpers.MustParseURL(srv.URL), false, true, 0)
+	require.NoError(t, err)
+
+	proxy := httptest.NewServer(http.HandlerFunc(p.ServeHTTP))
+
+	_, err = http.Get(proxy.URL + "/%3A%2F%2F")
+	require.NoError(t, err)
+
+	assert.Equal(t, "/%3A%2F%2F", gotEscapedPath)
+}
+
+type transportManagerMock struct {
+	roundTrippers map[string]http.RoundTripper
+}
+
+func (t *transportManagerMock) GetRoundTripper(name string) (http.RoundTripper, error) {
+	roundTripper, ok := t.roundTrippers[name]
+	if !ok {
+		return nil, errors.New("no transport for " + name)
+	}
+
+	return roundTripper, nil
+}
+
+func (t *transportManagerMock) GetTLSConfig(_ string) (*tls.Config, error) {
+	panic("implement me")
+}
+
+func (t *transportManagerMock) Get(_ string) (*dynamic.ServersTransport, error) {
+	panic("implement me")
+}