+sub iterate_start {
+ my ($self, $cb, @arg) = @_;
+ my $i = 0;
+ $self->{-iter} = [ \$i, $cb, @arg ];
+}
+
+# for PublicInbox::DS::next_tick, we only call this is if
+# PublicInbox::DS is already loaded
+sub event_step {
+ my ($self) = @_;
+ my ($i, $cb, @arg) = @{$self->{-iter}};
+ my $section = $self->{-section_order}->[$$i++];
+ delete($self->{-iter}) unless defined($section);
+ eval { $cb->($self, $section, @arg) };
+ warn "E: $@ in ${self}::event_step" if $@;
+ PublicInbox::DS::requeue($self) if defined($section);
+}
+