showToolbar method
void
showToolbar()
Shows the toolbar by inserting it into the context's overlay.
Implementation
void showToolbar() {
assert(_toolbar == null);
_toolbar = OverlayEntry(builder: _buildToolbar);
Overlay.of(context, rootOverlay: true, debugRequiredFor: debugRequiredFor)!
.insert(_toolbar!);
_toolbarController.forward(from: 0.0);
}