Exhaust request body before closing it (#5596)

Signed-off-by: bevisy <binbin36520@gmail.com>

discovery/triton/triton.go

@@ -17,6 +17,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"net/http"
 	"net/url"
@@ -157,7 +158,10 @@ func (d *Discovery) refresh(ctx context.Context) ([]*targetgroup.Group, error) {
 		return nil, errors.Wrap(err, "an error occurred when requesting targets from the discovery endpoint")
 	}
 
-	defer resp.Body.Close()
+	defer func() {
+		io.Copy(ioutil.Discard, resp.Body)
+		resp.Body.Close()
+	}()
 
 	data, err := ioutil.ReadAll(resp.Body)
 	if err != nil {