macro_rules! composing_normalize_to {
($(#[$meta:meta])*,
$normalize_to:ident,
$write:path,
$slice:ty,
$prolog:block,
$always_valid_utf:literal,
$as_slice:ident,
$fast:block,
$text:ident,
$sink:ident,
$composition:ident,
$composition_passthrough_bound:ident,
$undecomposed_starter:ident,
$pending_slice:ident,
$len_utf:ident,
) => { ... };
}