barchart.go
func (b *BarChart) SetBarGap(gap int32) {
	atomic.StoreInt32(&b.gap, gap)
}
func (b *BarChart) SetBarGap(gap int32) {
	atomic.StoreInt32(&b.gap, gap)
}
func ( b * BarChart ) SetBarGap ( gap int32 ) { atomic . StoreInt32 ( & b . gap , gap ) }
// SetGap sets the space width between two adjacent bars
SetGap sets the space width between two adjacent bars