io.Copy(io.Discard, conn)
			copying.Done()
		}()
	})).ts
	c := ts.Client()

	const bodySize = 256 << 10
	finalBit := make(byteFromChanReader, 1)
	req, _ := NewRequest("POST", ts.URL, io.MultiReader(io.LimitReader(neverEnding('x'), bodySize-1), finalBit))
	req.ContentLength = bodySize
	res, err := c.Do(req)
	if err := wantBody(res, err, "foo"); err != nil {
		t.Errorf("POST response: %v", err)
	}