progressbar.go
func (b *ProgressBar) SetSecondaryColors(fg, bg term.Attribute) {
	b.emptyFg, b.emptyBg = fg, bg
}
func (b *ProgressBar) SetSecondaryColors(fg, bg term.Attribute) {
	b.emptyFg, b.emptyBg = fg, bg
}
func ( b * ProgressBar ) SetSecondaryColors ( fg , bg term . Attribute ) { b . emptyFg , b . emptyBg = fg , bg }
// SetSecondaryColors sets new text and background colors for
// empty part of the ProgressBar
SetSecondaryColors sets new text and background colors for empty part of the ProgressBar