**Describe the situation**
https://markify.dev/p/zfrQMV2/text

**How to reproduce**
On aws `c5ad.24xlarge` run a query:

```
SET max_memory_usage = '100G', max_threads = 1000, max_insert_threads = 96

INSERT INTO wikistat WITH
    parseDateTimeBestEffort(extract(toLowCardinality(_path), 'pageviews-([\\d\\-]+)\\.gz$')) AS time,
    splitByChar(' ', line) AS values,
    splitByChar('.', values[1]) AS projects
SELECT
    time,
    projects[1] AS project,
    projects[2] AS subproject,
    values[2] AS path,
    CAST(values[3], 'UInt64') AS hits
FROM s3('https://....s3.eu-central-1.amazonaws.com/wikistat/original/*.gz', '...', '...', LineAsString, auto)
WHERE length(values) >= 3
```

Performance is not bad (22 million rows are inserted per second) but can be better.
{
    s.clear();
    readBackQuotedStringInto<true>(s, buf);
}
template <typename Vector>
void readCSVStringInto(Vector & s, ReadBuffer & buf, const FormatSettings::CSV & settings)
{
    if (buf.eof())
        throwReadAfterEOF();
    const char delimiter = settings.delimiter;
    const char maybe_quote = *buf.position();
    
    if (maybe_quote == delimiter)
        return;
    if ((settings.allow_single_quotes && maybe_quote == '\'') || (settings.allow_double_quotes && maybe_quote == '"'))
    {
        ++buf.position();
        
        while (!buf.eof())
        {
            char * next_pos = reinterpret_cast<char *>(memchr(buf.position(), maybe_quote, buf.buffer().end() - buf.position()));
            if (nullptr == next_pos)
                next_pos = buf.buffer().end();
            appendToStringOrVector(s, buf, next_pos);
            buf.position() = next_pos;
            if (!buf.hasPendingData())