fix: internal sACK flag not updated for client socket

src/socket/tcp.rs

@@ -1806,6 +1806,7 @@ impl<'a> Socket<'a> {
                 self.remote_seq_no = repr.seq_number + 1;
                 self.remote_last_seq = self.local_seq_no + 1;
                 self.remote_last_ack = Some(repr.seq_number);
+                self.remote_has_sack = repr.sack_permitted;
                 self.remote_win_scale = repr.window_scale;
                 // Remote doesn't support window scaling, don't do it.
                 if self.remote_win_scale.is_none() {