Function wait_readable2 

pub(crate) fn wait_readable2(
    a: RawFd,
    b: RawFd,
    timeout: Option<Duration>,
) -> Result<(bool, bool), String>

Poll two fds for readability at once (wayland socket + a wake pipe); returns (a_readable, b_readable), both false on timeout. Hangup counts as readable so a closed wake pipe unblocks its waiter.