<itemvalue="The widget to show under the pointer when a drag is under way. See [child] and [childWhenDragging] for information about what is shown at the location of the [Draggable] itself when a drag is under way."/>
<itemvalue="This entry will include the widget built by this builder in the overlay at the entry's position. To cause this builder to be called again, call [markNeedsBuild] on this overlay entry."/>
<itemvalue="Discards any resources used by this [OverlayEntry]. This method must be called after [remove] if the [OverlayEntry] is inserted into an [Overlay]. After this is called, the object is not in a usable state and should be discarded (calls to [addListener] will throw after the object is disposed). However, the listeners registered may not be immediately released until the widget built using this [OverlayEntry] is unmounted from the widget tree. This method should only be called by the object's owner."/>
<itemvalue="Remove this entry from the overlay. This should only be called once. This method removes this overlay entry from the overlay immediately. The UI will be updated in the same frame if this method is called before the overlay rebuild in this frame; otherwise, the UI will be updated in the next frame. This means that it is safe to call during builds, but also that if you do call this after the overlay rebuild, the UI will not update until the next frame (i.e. many milliseconds later)."/>