How can I change multiline for c3js bar chart x axis tick text

How can I change the multiline for c3js bar chart x axis tick text in normal horizontal mode?

****in normal horizontal mode, multiline is not working and how can I fix?**
As I noticed if included > rotate: 90, multiline is not working. but not okay to show without rotate because most of the tick values are long.**
`data: {
x: 'x',
columns: columns,
type: 'bar',
labels: true
},
axis: {
x: {
type: 'category',
tick: {
rotate: 90,
multiline: true
}
,
height: heightForX
},`

**multiline is correctly displayed in vertical mode.**
`axis: {
rotated: true,
x: {
type: 'category',
label: {
text: labelY,
position: 'outer-middle'
}
,
tick: {
multiline: true,
}
}
},`

but cs3j sample, multiline is working with rotate mode
https://c3js.org/samples/axes_x_tick_rotate.html