+There is also more elaborative way to call C<to_hash> like this:
+
+ my $hash = $isis->to_hash({
+ mfn => 42,
+ include_subfields => 1,
+ });
+
+Each option controll creation of hash:
+
+=over 4
+
+=item mfn
+
+Specify MFN number of record
+
+=item include_subfields
+
+This option will create additional key in hash called C<subfields> which will
+have original record subfield order and index to that subfield like this:
+
+ 902 => [ {
+ a => ["a1", "a2", "a3", "a4", "a5"],
+ b => ["b1", "b2"],
+ c => "c1",
+ subfields => ["a", 0, "a", 1, "a", 2, "b", 0, "a", 3, "b", 1, "c", 0, "a", 4],
+ } ],
+
+=item join_subfields_with
+
+Define delimiter which will be used to join repeatable subfields. You can
+specify option here instead in L</new> if you want to have per-record control.
+
+=item hash_filter
+
+You can override C<hash_filter> defined in L</new> using this option.
+
+=back
+