// should not result in any allocations.
// This can be used to reset the underlying []byte of an existing Buffer.
func TestNewBufferShallow(t *testing.T) {
	testenv.SkipIfOptimizationOff(t)
	n := testing.AllocsPerRun(1000, func() {
		buf = *NewBuffer(testBytes)
	})
	if n > 0 {
		t.Errorf("allocations occurred while shallow copying")
	}
	check(t, "NewBuffer", &buf, testString)
}