getTextCharset example

$e = (new Email())->from('me@example.com')->to('you@example.com');
        $e->html('html content');
        $e->text('text content');
        $this->assertEquals(new AlternativePart($text, $html), $e->getBody());
    }

    public function testGenerateBodyWithTextAndHtmlNotUtf8()
    {
        $e = (new Email())->from('me@example.com')->to('you@example.com');
        $e->html('html content', 'iso-8859-1');
        $e->text('text content', 'iso-8859-1');
        $this->assertEquals('iso-8859-1', $e->getTextCharset());
        $this->assertEquals('iso-8859-1', $e->getHtmlCharset());
        $this->assertEquals(new AlternativePart(new TextPart('text content', 'iso-8859-1'), new TextPart('html content', 'iso-8859-1', 'html')), $e->getBody());
    }

    public function testGenerateBodyWithTextContentAndAttachedFile()
    {
        [$text, $html, $filePart, $file, $imagePart, $image] = $this->generateSomeParts();
        $e = (new Email())->from('me@example.com')->to('you@example.com');
        $e->addPart(new DataPart($file));
        $e->text('text content');
        $this->assertEquals(new MixedPart($text, $filePart), $e->getBody());
    }

        if ($emails = $email->getCc()) {
            $request['Destination']['CcAddresses'] = $this->stringifyAddresses($emails);
        }
        if ($emails = $email->getBcc()) {
            $request['Destination']['BccAddresses'] = $this->stringifyAddresses($emails);
        }
        if ($email->getTextBody()) {
            $request['Content']['Simple']['Body']['Text'] = new Content([
                'Data' => $email->getTextBody(),
                'Charset' => $email->getTextCharset(),
            ]);
        }
        if ($email->getHtmlBody()) {
            $request['Content']['Simple']['Body']['Html'] = new Content([
                'Data' => $email->getHtmlBody(),
                'Charset' => $email->getHtmlCharset(),
            ]);
        }
        if ($emails = $email->getReplyTo()) {
            $request['ReplyToAddresses'] = $this->stringifyAddresses($emails);
        }
        

$subjectFormatter = $this->getSubjectFormatter($message->getSubject());
            $message->subject($subjectFormatter->format($this->getHighestRecord($records)));
        }

        if ($this->getFormatter() instanceof HtmlFormatter) {
            if ($message->getHtmlCharset()) {
                $message->html($content, $message->getHtmlCharset());
            } else {
                $message->html($content);
            }
        } else {
            if ($message->getTextCharset()) {
                $message->text($content, $message->getTextCharset());
            } else {
                $message->text($content);
            }
        }

        return $message;
    }

    protected function getHighestRecord(array $records): array|LogRecord
    {