func (pt *PassThru) Close() error {
	err := pt.ReadCloser.Close()
	return err
}
Close overrides underlying io.ReadCloser Close method
package progressbar
import (
	"io"
)
type PassThru struct {
	io.ReadCloser
	Total *chan int64  
}
func (pt *PassThru) Read(p []byte) (int, error) {
	n, err := pt.ReadCloser.Read(p)
	*pt.Total <- int64(n)
	return n, err
}