7 string references to 'Charset'

DataPart::__sleep in vendor/symfony/mime/Part/DataPart.php
DataPart::__wakeup in vendor/symfony/mime/Part/DataPart.php
MessageConverter::createEmailFromAlternativePart in vendor/symfony/mime/MessageConverter.php
MessageConverter::createEmailFromTextPart in vendor/symfony/mime/MessageConverter.php
Response::prepare in vendor/symfony/http-foundation/Response.php: Prepares the Response before it is sent to the client.
TextPart::getPreparedHeaders in vendor/symfony/mime/Part/TextPart.php
TextPart::__sleep in vendor/symfony/mime/Part/TextPart.php