To `JSONEachRow`
{
    skipWhitespaceIfAny(istr);
    assertChar(':', istr);
    skipWhitespaceIfAny(istr);
}
void JSONEachRowRowInputFormat::skipUnknownField(const StringRef & name_ref)
{
    if (!format_settings.skip_unknown_fields)
        throw Exception("Unknown field found while parsing JSONEachRow format: " + name_ref.toString(), ErrorCodes::INCORRECT_DATA);
    skipJSONField(*in, name_ref);
}
void JSONEachRowRowInputFormat::readField(size_t index, MutableColumns & columns)