pub type zxio_token_resolver_t = Option<unsafe extern "C" fn(io: *mut zxio_t, type_: zxio_token_type_t) -> zx_handle_t>;
pub enum zxio_token_resolver_t { None, Some(unsafe extern "C" fn(*mut zxio_tag, u32) -> u32), }
No value.
Some value of type T.
T