Making streams in PHP/Laravel

LaravelUsage.php

<?php
public function writeQueryAsCsvFileToStorage() {
    $disk = Storage::disk('yourDiskNameHer');
    // optional: ensure file doesn't exist:
    // $disk->delete($filePath);

    $cursor = $this->getQuery()
            ->toBase() // +-10x speed improvement, skip making laravel models
            ->cursor() // avoid loading whole result set into memory.
            ->map(fn ($item) => $this->map((array) $item));
    // writes all data (1 by 1) to a temporary file then we can then stream to external disk.
    $stream = StreamHelper::streamCsvAssoc($cursor);
    $disk->writeStream($filePath, $stream);
    fclose($stream);
}

StreamHelper.php

<?php
class StreamHelper
{
    public static function streamCsv(iterable $iterator, string $separator = ',', string $enclosure = '"', string $escape = '\\')
    {
        return self::stream($iterator, function ($stream, $value) use ($escape, $enclosure, $separator) {
            fputcsv($stream, $value, $separator, $enclosure, $escape);
        });
    }

    public static function streamCsvAssoc(iterable $iterator, string $separator = ',', string $enclosure = '"', string $escape = '\\')
    {
        $first = true;

        return self::stream($iterator, function ($stream, $value) use (&$first, $escape, $enclosure, $separator) {
            if ($first) {
                fputcsv($stream, array_keys($value), $separator, $enclosure, $escape);
                $first = false;
            }
            fputcsv($stream, array_values($value), $separator, $enclosure, $escape);
        });
    }

    public static function streamJsonList(iterable $iterator, int $flags = 0, int $depth = 512)
    {
        $stream = tmpfile();
        fwrite($stream, '[');
        $first = true;
        foreach ($iterator as $value) {
            if (!$first) {
                fwrite($stream, ',');
            } else {
                $first = false;
            }
            fwrite($stream, json_encode($value, $flags, $depth));
        }
        fwrite($stream, ']');
        rewind($stream);

        return $stream;
    }

    /**
     * @param iterable $iterator
     * @param $writeFunction (stream, value)
     *
     * @return resource
     */
    public static function stream(iterable $iterator, callable $writeFunction)
    {
        $stream = tmpfile();
        if (false === $stream) {
            throw new \Exception('failed making stream');
        }
        foreach ($iterator as $value) {
            $writeFunction($stream, $value);
        }
        rewind($stream);

        return $stream;
    }
}