add Log() and Logf()

log.go

@@ -0,0 +1,11 @@
+package httppb
+
+import "fmt"
+
+func (pb *HttpRequest) Log(a ...any) {
+	pb.Logs = append(pb.Logs, fmt.Sprint(a...))
+}
+
+func (pb *HttpRequest) Logf(s string, a ...any) {
+	pb.Logs = append(pb.Logs, fmt.Sprintf(s, a...))
+}