filters.go
func ApplyRuleIf(condition, rule Ruler) Ruler {
	return &apply{
		condition: condition,
		rule:      rule,
	}
}
func ApplyRuleIf(condition, rule Ruler) Ruler {
	return &apply{
		condition: condition,
		rule:      rule,
	}
}
func ApplyRuleIf ( condition , rule Ruler ) Ruler { return & apply { condition : condition , rule : rule , } }
// ApplyRuleIf test if condition is true than apply rule. If condition is false
// do nothing, return true.
ApplyRuleIf test if condition is true than apply rule . If condition is false do nothing return true .