If we're not using the colorizer, you can call io.Copy like it used to,
instead of overwriting the variable. I think that would be simpler than
the adapter type.

```go
if !term.IsTerminal(os.Stdout) {
  if _, err := io.Copy(os.Stdout, resp.Body); err != nil {
    log.Fatal(err)
  }
  return
}
```