Fix read op is not reading more than 64K

After several tests using hsbench I have seen that the bw reported by hsbench is not equal to the network bw.
It looks like hsbench is closing the connection before getting the whole obj for medium object or larger(bigger than 512K).

hsbench.go

@@ -20,6 +20,7 @@ import (
 	"github.com/aws/aws-sdk-go/aws/credentials"
 	"github.com/aws/aws-sdk-go/aws/session"
 	"github.com/aws/aws-sdk-go/service/s3"
+	"io"
 	"log"
 	"math"
 	"math/rand"
@@ -514,6 +515,24 @@ func runUpload(thread_num int, fendtime time.Time, stats *Stats) {
 	atomic.AddInt64(&running_threads, -1)
 }
 
+func readBody(r io.Reader) (int64, error) {
+	var bytesRead int64 = 0
+	buf := make([]byte, 8192)
+	for {
+		n, err := r.Read(buf)
+		if n > 0 {
+			bytesRead += int64(n)
+		}
+		if err != nil {
+			if err == io.EOF {
+				return bytesRead, nil
+			} else {
+				return bytesRead, err
+			}
+		}
+	}
+}
+
 func runDownload(thread_num int, fendtime time.Time, stats *Stats) {
 	errcnt := 0
 	svc := s3.New(session.New(), cfg)
@@ -540,15 +559,21 @@ func runDownload(thread_num int, fendtime time.Time, stats *Stats) {
 		err := req.Send()
 		end := time.Now().UnixNano()
 		stats.updateIntervals(thread_num)
-
 		if err != nil {
 			errcnt++
 			stats.addSlowDown(thread_num)
 			log.Printf("download err", err)
 		} else {
-			resp.Body.Close()
+			var bytesRead int64 = 0
+			defer resp.Body.Close()
+			bytesRead, err := readBody(resp.Body)
 			// Update the stats
-			stats.addOp(thread_num, object_size, end-start)
+			stats.addOp(thread_num, bytesRead, end-start)
+			if err != nil {
+				errcnt++
+				stats.addSlowDown(thread_num)
+				log.Printf("download err", err)
+			}
 		}
 		if errcnt > 2 {
 			break