Is there support for adding an icon above any date in a Gantt chart?

Hello,
Is there support for adding an icon above any date in a Gantt chart?
Are there any examples you can refer to?

For example,
data is as follows

data:[{
id: 1,
start_date:'xxxxxx',
end_date:'xxxxxx',
flag:'2024-04-07 09:00'
},{
id: 1,
start_date:'xxxxxx',
end_date:'xxxxxx'
}]

I want to add an icon to the date of the attribute value when there is a flag attribute, for example 2024-04-07 09:00

Are there any examples you can refer to?