Plugins: Add support for HTTP logger (#46578)

pkg/infra/httpclient/httpclientprovider/testing.go

@@ -1,6 +1,8 @@
 package httpclientprovider
 
 import (
+	"bytes"
+	"io/ioutil"
 	"net/http"
 
 	"github.com/grafana/grafana-plugin-sdk-go/backend/httpclient"
@@ -13,6 +15,10 @@ type testContext struct {
 func (c *testContext) createRoundTripper(name string) http.RoundTripper {
 	return httpclient.RoundTripperFunc(func(req *http.Request) (*http.Response, error) {
 		c.callChain = append(c.callChain, name)
-		return &http.Response{StatusCode: http.StatusOK, Request: req}, nil
+		return &http.Response{
+			StatusCode: http.StatusOK,
+			Request:    req,
+			Body:       ioutil.NopCloser(bytes.NewBufferString("")),
+		}, nil
 	})
 }