// NewChecker ensures that content with the specified length is read from rc.
// Calling Close on this will close upstream.
func NewChecker(rc io.ReadCloser, h hash.Hash, wantSum []byte, length int64) *Checker {
	return &Checker{c: rc, r: ioutil.HardLimitReader(rc, length), h: h, want: wantSum}
}

// Read satisfies io.Reader
func (c Checker) Read(p []byte) (n int, err error) {
	n, err = c.r.Read(p)
	if n > 0 {
		c.h.Write(p[:n])
	}

					gotSelected.cached = nil
					gotSelected.reusable = false
				}
				if !reflect.DeepEqual(gotSelected, tt.wantSelected) {
					wantM, _ := tt.wantSelected.xlmeta()
					gotM, _ := gotSelected.xlmeta()
					t.Errorf("resolve() gotSelected = \n%#v, want \n%#v", *gotM, *wantM)
				}
			})
		}
	}