fix: do not use errors.Join, just use custom error approach

client.go

@@ -1244,10 +1244,10 @@ func (c *Client) execute(req *Request) (*Response, error) {
 
 	if err != nil || req.notParseResponse || c.notParseResponse {
 		response.setReceivedAt()
-		logErr := responseLogger(c, response)
-		if logErr != nil {
+		if logErr := responseLogger(c, response); logErr != nil {
 			return response, wrapErrors(logErr, err)
-		} else if err != nil {
+		}
+		if err != nil {
 			return response, err
 		}
 		return response, nil

util_test.go

@@ -6,6 +6,7 @@ package resty
 
 import (
 	"bytes"
+	"errors"
 	"mime/multipart"
 	"testing"
 )
@@ -89,3 +90,18 @@ func TestWriteMultipartFormFileReaderError(t *testing.T) {
 	assertNotNil(t, err)
 	assertEqual(t, "read error", err.Error())
 }
+
+func TestRestyErrorFuncs(t *testing.T) {
+	ne1 := errors.New("new error 1")
+	nie1 := errors.New("inner error 1")
+
+	e := wrapErrors(ne1, nie1)
+	assertEqual(t, "new error 1", e.Error())
+	assertEqual(t, "inner error 1", errors.Unwrap(e).Error())
+
+	e = wrapErrors(ne1, nil)
+	assertEqual(t, "new error 1", e.Error())
+
+	e = wrapErrors(nil, nie1)
+	assertEqual(t, "inner error 1", e.Error())
+}