Macro impl_expected_write_hook

macro_rules! impl_expected_write_hook {
    ( ($fn: expr) ( $socket:expr, $buffer:expr, $length:expr), $timeout:expr) => { ... };
    ( ($fn: expr) ( $socket:expr, $buffer:expr, $length:expr, $($arg: expr),* $(,)* ), $timeout:expr) => { ... };
}