func NewColumnIteratorWithTimestampFormat(format Format, reader io.Reader, timestampFormat string) *Iterator {
	return NewIterator(reader, ColumnUnmarshallerWithTimestamp(format, timestampFormat))
}
func NewColumnIteratorWithTimestampFormat(format Format, reader io.Reader, timestampFormat string) *Iterator {
	return NewIterator(reader, ColumnUnmarshallerWithTimestamp(format, timestampFormat))
}
// NewColumnIteratorWithTimestampFormat creates a new iterator for column data with timestamp.