headerHelpStyle property
final
Overrides the header's default help text style.
The help text (also referred to as "supporting text" in the Material spec) is usually a prompt to the user at the top of the header (i.e. 'Select date').
The TextStyle.color of the headerHelpStyle is not used, headerForegroundColor is used instead.
See also: DatePickerDialog.helpText, which specifies the help text.
Implementation
final TextStyle? headerHelpStyle;