macro_rules! assert_try_writeable_parts_eq {
($actual_writeable:expr, $expected_str:expr, $expected_parts:expr $(,)?) => { ... };
($actual_writeable:expr, $expected_str:expr, $expected_result:expr, $expected_parts:expr $(,)?) => { ... };
($actual_writeable:expr, $expected_str:expr, $expected_result:expr, $expected_parts:expr, $($arg:tt)+) => { ... };
}