prints a horizontal line to the whole width.
The line is drawn using default char -, you may choose any other char.
The default is a single line char. By specifying doubleLine = true,
a double line is drawn with =.
write column chunk, flex (defaults to 1). Flex determines
the number of parts of the row this column shall occupy. Think
of flex like a fraction. If the row has 10 columns and this
column has a flex = 3, then the column shall occupy 3/10ths or
30% of the width of the row. [...]