**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.
++buf.position();
        skipWhitespaceIfAny(buf);
        if (!buf.eof() && *buf.position() == ']') 
        {
            ++buf.position();
            return;
        }
        while (true)
        {
            skipJSONField(buf, name_of_field);
            skipWhitespaceIfAny(buf);
            if (!buf.eof() && *buf.position() == ',')
            {
                ++buf.position();
                skipWhitespaceIfAny(buf);
            }
            else if (!buf.eof() && *buf.position() == ']')
            {
                ++buf.position();
                break;
            }
            else
                throw Exception("Unexpected symbol for key '" + name_of_field.toString() + "'", ErrorCodes::INCORRECT_DATA);
        }
    }
    else if (*buf.position() == '{') 
    {
        ++buf.position();
        skipWhitespaceIfAny(buf);
        while (!buf.eof() && *buf.position() != '}')