[HttpClient] accept headers when CURLE_RECV_ERROR is received before the content

Author: nicolas-grekas

Response/CurlResponse.php

@@ -290,6 +290,10 @@ private static function perform(ClientState $multi, array &$responses = null): v
                     }
                 }
 
+                if (\CURLE_RECV_ERROR === $result && 'H' === $waitFor[0] && 400 <= ($responses[(int) $ch]->info['http_code'] ?? 0)) {
+                    $multi->handlesActivity[$id][] = new FirstChunk();
+                }
+
                 $multi->handlesActivity[$id][] = null;
                 $multi->handlesActivity[$id][] = \in_array($result, [\CURLE_OK, \CURLE_TOO_MANY_REDIRECTS], true) || '_0' === $waitFor || curl_getinfo($ch, \CURLINFO_SIZE_DOWNLOAD) === curl_getinfo($ch, \CURLINFO_CONTENT_LENGTH_DOWNLOAD) ? null : new TransportException(sprintf('%s for "%s".', curl_strerror($result), curl_getinfo($ch, \CURLINFO_EFFECTIVE_URL)));
             }