implement TX v4 experimental

[jptosso]

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[jcchavezs]

IMHO this interface is meaningless, if someone wants to access this fields they can create their own convenience interface.

[jptosso]

package test

import (
	"context"
	"testing"

	"github.com/corazawaf/coraza/v3"
	"github.com/corazawaf/coraza/v3/types"
)

type transaction interface {
	types.Transaction
	Context() context.Context
}

func TestCoraza(t *testing.T) {
	waf, _ := coraza.NewWAF(coraza.NewWAFConfig())
	tx, ok := waf.NewTransaction().(transaction)
	if !ok {
		t.Errorf("cannot access Token")
	}
	tx.Context().Value("key")
}

It is not possible to access internal fields using this hack

Context IS required to control timeout for certain actions, among others

[jcchavezs]

This is controversial and that is why I'd like to use use cases before exposing this. Why not a time.Time? Not saying that is the answer, just saying we need concrete use cases.