Fix Client returning disconnected because of VFS errors

libraries/WiFi/src/WiFiClient.cpp

@@ -438,9 +438,23 @@ uint8_t WiFiClient::connected()
     if (_connected) {
         uint8_t dummy;
         int res = recv(fd(), &dummy, 0, MSG_DONTWAIT);
-        if (res <= 0 && errno != EWOULDBLOCK) {
-            _connected = false;
-            log_i("Disconnected: RES: %d, ERR: %d", res, errno);
+        switch (errno) {
+            case EWOULDBLOCK:
+            case ENOENT: //caused by vfs
+                _connected = true;
+                break;
+            case ENOTCONN:
+            case EPIPE:
+            case ECONNRESET:
+            case ECONNREFUSED:
+            case ECONNABORTED:
+                _connected = false;
+                log_d("Disconnected: RES: %d, ERR: %d", res, errno);
+                break;
+            default:
+                log_i("Unexpected: RES: %d, ERR: %d", res, errno);
+                _connected = true;
+                break;
         }
     }
     return _connected;