fix: 内存模式下，设置单个单元格内容格式，内存模式会失效，导致内存不断堆叠溢出

[mingdiantianxia]

$config     = ['path' => '/'];
$excel = new \Vtiful\Kernel\Excel($config); 
$fileObject = $excel->constMemory('test.xlsx', '内存占用', false);
for ($index = 0; $index < 10000; $index++) {
    for ($column = 0; $column < 300; $column++) {
        $mem = self::getMemoryUsage('MemRealUsage');
        $mem = $mem / (1024 * 1024);
        $fileObject->insertText($index+1, $column, floatval($mem), 'Max$#,##0.00;Max$-#,##0.00');
        var_dump($mem);
    }
}
$filePath = $fileObject->output();
$fileObject->close();

[c-c-j]

Hello, have you resolved this issue?

[c-c-j]

@viest

[c-c-j]

The extended and dependent versions I am using are as follows. I actively called the close method to destroy resources, but the server content remains consistent and is being added
@viest

[videni]

I also have this issue.

[videni]

You can use following example to reproduce it quickly.

<?php

// Under const memory, insertDate and insertText have the problem of memory leakage. 
// By executing the following program, you can observe the continuous growth of memory using the top command

// I also created an issue [here](https://github.com/jmcnamara/libxlsxwriter/issues/453)

$config = ['path' => __DIR__];

$excel = new \Vtiful\Kernel\Excel($config);

$filename = 'million_rows.xlsx';
$excel->constMemory($filename);
// $excel->fileName($filename);

$excel->header(['id', 'first_name', 'last_name', 'born_at']);

echo "my pid-".getmypid();

sleep(3);

$list = function() {
    for ($i = 1; $i <= 1000000; $i++) {
        yield [$i,  'Jane', 'Doe', time()];
    }
};

foreach($list() as $row) {
    $currentRow = $excel->getCurrentLine();

    $excel->insertDate(
        $currentRow,
        3,
        $row[3]
    );
    $row[3] = null;

    $excel->data([$row]);
}

$excel->output();

echo "Excel file with 1 million rows created successfully!\n";