is-deeply (csv (in => $file, after_in => &Push), [ [< foo bar baz A >], [ 1, 2, 3, "A" ], [ 2, "a b", "", "A" ], ], "AOA ith after_in callback");

sub Change (Text::CSV $c, CSV::Field %f) { %f<baz> = "A"; }

is-deeply (csv (in => $file, headers => "auto", after_in => &Change), [ { foo => 1, bar => 2, baz => "A" }, { foo => 2, bar => "a b", baz => "A" }, ], "AOH with after_in callback");