func (b *Builder) Set(n, v string) *Builder {
	for i, a := range b.add {
		if a.Name == n {
			b.add[i].Value = v
			return b
		}
	}
	b.add = append(b.add, Label{Name: n, Value: v})

	return b
}
func (b *Builder) Set(n, v string) *Builder {
	for i, a := range b.add {
		if a.Name == n {
			b.add[i].Value = v
			return b
		}
	}
	b.add = append(b.add, Label{Name: n, Value: v})

	return b
}
func ( b * Builder ) Set ( n , v string ) * Builder { for i , a := range b . add { if a . Name == n { b . add [ i ] . Value = v return b } } b . add = append ( b . add , Label { Name : n , Value : v } ) return b }
// Set the name/value pair as a label.
Set the name / value pair as a label .