$writer = new \CSVTimeseries\Writer;
$writer->to(__DIR__ . '/data/');
$i = 1;
while ($i < 1000) {
    //it adds current timestamp to the record and saves the record to a buffer
    $writer->add(['test', $i++]);
}
//it writers the buffer to a disk and creates single file per day, 
//for example: "data/2020/20200931.csv"
//save call is optional. script shutdown triggers it.
$writer->save();


$reader = new \CSVTimeseries\Reader;
$reader->from(__DIR__ . '/data/');
while ($line = $reader->next()) {
    //first cell is timestamp, for example: 2020-08-28T19:25:09+00:00
    $ts = array_shift($line);
    //print assigned data
    print_r($line);
}