panelPoppingBehavior property
When any of the BackPressBehavior is given, if the user taps back button, panel's state is checked according to BackPressBehavior and animates accordingly (if needed).
With this, you can even control the behavior of the panel, that WHAT will happen AFTER the panel is animated. If you want to pop the panel immediately after animation OR wait for the user to tap again in order to pop the panel.
If no animation is played (e.g., the panel already satisfies the BackPressBehavior), the behavior would be set to PanelPoppingBehavior.POP_IMMEDIATELY.
Note that, this is simply ignored when BackPressBehavior.POP is given, or any of the persistent behavior is given in BackPressBehavior.
Also valid for two-state panels.
Default : PanelPoppingBehavior.POP_AFTER_TAP
Implementation
final PanelPoppingBehavior panelPoppingBehavior;