[HttpClient] Fix a crash when calling CurlHttpClient::__destruct()

Author: dunglas

CurlHttpClient.php

@@ -301,15 +301,20 @@ public function stream($responses, float $timeout = null): ResponseStreamInterfa
     public function __destruct()
     {
         $this->multi->pushedResponses = [];
-        if (\defined('CURLMOPT_PUSHFUNCTION')) {
-            curl_multi_setopt($this->multi->handle, CURLMOPT_PUSHFUNCTION, null);
-        }
 
-        $active = 0;
-        while (CURLM_CALL_MULTI_PERFORM === curl_multi_exec($this->multi->handle, $active));
+        if (\is_resource($this->multi->handle)) {
+            if (\defined('CURLMOPT_PUSHFUNCTION')) {
+                curl_multi_setopt($this->multi->handle, CURLMOPT_PUSHFUNCTION, null);
+            }
+
+            $active = 0;
+            while (CURLM_CALL_MULTI_PERFORM === curl_multi_exec($this->multi->handle, $active));
+        }
 
         foreach ($this->multi->openHandles as [$ch]) {
-            curl_setopt($ch, CURLOPT_VERBOSE, false);
+            if (\is_resource($ch)) {
+                curl_setopt($ch, CURLOPT_VERBOSE, false);
+            }
         }
     }