fileservice: drain response reader to ensure connection reuse

pkg/fileservice/aliyun_sdk.go

@@ -498,7 +498,14 @@ func (a *AliyunSDK) getObject(ctx context.Context, key string, min *int64, max *
 			if err != nil {
 				return nil, err
 			}
-			return r, nil
+			return &readCloser{
+				r: r,
+				closeFunc: func() error {
+					// drain
+					io.Copy(io.Discard, r)
+					return r.Close()
+				},
+			}, nil
 		},
 		*min,
 		IsRetryableError,

pkg/fileservice/aws_sdk_v2.go

@@ -650,7 +650,14 @@ func (a *AwsSDKv2) getObject(ctx context.Context, min *int64, max *int64, params
 			if err != nil {
 				return nil, err
 			}
-			return output.Body, nil
+			return &readCloser{
+				r: output.Body,
+				closeFunc: func() error {
+					// drain
+					io.Copy(io.Discard, output.Body)
+					return output.Body.Close()
+				},
+			}, nil
 		},
 		*min,
 		IsRetryableError,

pkg/fileservice/minio_sdk.go

@@ -568,7 +568,14 @@ func (a *MinioSDK) getObject(ctx context.Context, key string, min *int64, max *i
 					return nil, err
 				}
 			}
-			return obj, nil
+			return &readCloser{
+				r: obj,
+				closeFunc: func() error {
+					// drain
+					io.Copy(io.Discard, obj)
+					return obj.Close()
+				},
+			}, nil
 		},
 		*min,
 		IsRetryableError,

pkg/fileservice/qcloud_sdk.go

@@ -484,7 +484,14 @@ func (a *QCloudSDK) getObject(ctx context.Context, key string, min *int64, max *
 					if err != nil {
 						return nil, err
 					}
-					return resp.Body, nil
+					return &readCloser{
+						r: resp.Body,
+						closeFunc: func() error {
+							// drain
+							io.Copy(io.Discard, resp.Body)
+							return resp.Body.Close()
+						},
+					}, nil
 				},
 				maxRetryAttemps,
 				IsRetryableError,