Aggiornato Composer

vendor/symfony/mime/Part/TextPart.php

@@ -42,7 +42,7 @@ class TextPart extends AbstractPart
     /**
      * @param resource|string $body
      */
-    public function __construct($body, ?string $charset = 'utf-8', string $subtype = 'plain', string $encoding = null)
+    public function __construct($body, ?string $charset = 'utf-8', string $subtype = 'plain', ?string $encoding = null)
     {
         unset($this->_headers);
 
@@ -197,6 +197,7 @@ class TextPart extends AbstractPart
         // convert resources to strings for serialization
         if (null !== $this->seekable) {
             $this->body = $this->getBody();
+            $this->seekable = null;
         }
 
         $this->_headers = $this->getHeaders();