[#352] container: Implement iterators over attributes

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

container/container_test.go

@@ -2,6 +2,7 @@ package container_test
 
 import (
 	"crypto/sha256"
+	"maps"
 	"strconv"
 	"testing"
 	"time"
@@ -159,9 +160,9 @@ func TestContainer_Attribute(t *testing.T) {
 	val.SetAttribute(attrKey2, attrVal2)
 
 	var i int
-	val.IterateUserAttributes(func(key, val string) {
+	for range val.UserAttributes() {
 		i++
-	})
+	}
 	require.Equal(t, 1, i)
 
 	var msg v2container.Container
@@ -177,11 +178,7 @@ func TestContainer_Attribute(t *testing.T) {
 	require.Equal(t, attrVal1, val2.Attribute(attrKey1))
 	require.Equal(t, attrVal2, val2.Attribute(attrKey2))
 
-	m := map[string]string{}
-
-	val2.IterateAttributes(func(key, val string) {
-		m[key] = val
-	})
+	m := maps.Collect(val2.Attributes())
 
 	require.GreaterOrEqual(t, len(m), 2)
 	require.Equal(t, attrVal1, m[attrKey1])