fix RST storm: tcp_recved before tcp_close in proxy_poll_cb cleanup

src/tcp_proxy.c

@@ -325,7 +325,10 @@ static err_t proxy_poll_cb(void *arg, struct tcp_pcb *pcb) {
                    (unsigned long long)pc->remote_stream_id, pc->closing_rem, pc->closing_sent,
                    pc->pcb->cwnd, pc->pcb->snd_buf, (void*)pc->pcb->unsent, (void*)pc->pcb->unacked);
         struct tcp_pcb *save = pc->pcb;
-        tcp_arg(save, NULL); pc->pcb = NULL; tcp_close(save);
+        tcp_arg(save, NULL); pc->pcb = NULL;
+        { uint16_t wnd_gap = TCP_WND_MAX(save) - save->rcv_wnd;
+          if (wnd_gap > 0) tcp_recved(save, wnd_gap); }
+        tcp_close(save);
         struct tcp_proxy *proxy = pc->proxy;
         struct proxy_conn **prev = &proxy->conns;
         while (*prev) { if (*prev == pc) { *prev = pc->next; proxy->conn_count--; break; } prev = &(*prev)->next; }