hoverOpenDelay property
final
The duration to wait before opening the menu when the button is hovered.
Because MenuBar children can only be opened by hover if a sibling SubmenuButton is already open, providing a hoverOpenDelay to direct children of a MenuBar will throw an assertion error. This is to avoid the case where the hoverOpenDelay for a SubmenuButton is longer than the duration of a sibling's closing animation, which leads to that menu never opening.
Defaults to Duration.zero.
Implementation
final Duration hoverOpenDelay;