update dependencies

vendor/github.com/Azure/go-autorest/autorest/sender.go

@@ -23,11 +23,29 @@ import (
 	"net/http"
 	"net/http/cookiejar"
 	"strconv"
+	"sync"
 	"time"
 
 	"github.com/Azure/go-autorest/tracing"
 )
 
+// there is one sender per TLS renegotiation type, i.e. count of tls.RenegotiationSupport enums
+const defaultSendersCount = 3
+
+type defaultSender struct {
+	sender Sender
+	init   *sync.Once
+}
+
+// each type of sender will be created on demand in sender()
+var defaultSenders [defaultSendersCount]defaultSender
+
+func init() {
+	for i := 0; i < defaultSendersCount; i++ {
+		defaultSenders[i].init = &sync.Once{}
+	}
+}
+
 // used as a key type in context.WithValue()
 type ctxSendDecorators struct{}
 
@@ -107,26 +125,31 @@ func SendWithSender(s Sender, r *http.Request, decorators ...SendDecorator) (*ht
 }
 
 func sender(renengotiation tls.RenegotiationSupport) Sender {
-	// Use behaviour compatible with DefaultTransport, but require TLS minimum version.
-	defaultTransport := http.DefaultTransport.(*http.Transport)
-	transport := &http.Transport{
-		Proxy:                 defaultTransport.Proxy,
-		DialContext:           defaultTransport.DialContext,
-		MaxIdleConns:          defaultTransport.MaxIdleConns,
-		IdleConnTimeout:       defaultTransport.IdleConnTimeout,
-		TLSHandshakeTimeout:   defaultTransport.TLSHandshakeTimeout,
-		ExpectContinueTimeout: defaultTransport.ExpectContinueTimeout,
-		TLSClientConfig: &tls.Config{
-			MinVersion:    tls.VersionTLS12,
-			Renegotiation: renengotiation,
-		},
-	}
-	var roundTripper http.RoundTripper = transport
-	if tracing.IsEnabled() {
-		roundTripper = tracing.NewTransport(transport)
-	}
-	j, _ := cookiejar.New(nil)
-	return &http.Client{Jar: j, Transport: roundTripper}
+	// note that we can't init defaultSenders in init() since it will
+	// execute before calling code has had a chance to enable tracing
+	defaultSenders[renengotiation].init.Do(func() {
+		// Use behaviour compatible with DefaultTransport, but require TLS minimum version.
+		defaultTransport := http.DefaultTransport.(*http.Transport)
+		transport := &http.Transport{
+			Proxy:                 defaultTransport.Proxy,
+			DialContext:           defaultTransport.DialContext,
+			MaxIdleConns:          defaultTransport.MaxIdleConns,
+			IdleConnTimeout:       defaultTransport.IdleConnTimeout,
+			TLSHandshakeTimeout:   defaultTransport.TLSHandshakeTimeout,
+			ExpectContinueTimeout: defaultTransport.ExpectContinueTimeout,
+			TLSClientConfig: &tls.Config{
+				MinVersion:    tls.VersionTLS12,
+				Renegotiation: renengotiation,
+			},
+		}
+		var roundTripper http.RoundTripper = transport
+		if tracing.IsEnabled() {
+			roundTripper = tracing.NewTransport(transport)
+		}
+		j, _ := cookiejar.New(nil)
+		defaultSenders[renengotiation].sender = &http.Client{Jar: j, Transport: roundTripper}
+	})
+	return defaultSenders[renengotiation].sender
 }
 
 // AfterDelay returns a SendDecorator that delays for the passed time.Duration before