Display a C<$message> in the flash of type C<$type>. Multiple calls of
C<flash> on the same C<$self> will be merged by type.
-On the client side the flash of this type will be cleared before the
-message is shown.
+On the client side the flashes of all types will be cleared after each
+successful ClientJS call that did not end with C<$js-E<gt>error(...)>.
=item C<error $message>