// PORT TARGET: utils/src/eventfd.rs (Linux only)
// Status: skeleton (no impl)
//
// macOS analogue: kqueue EVFILT_USER + NOTE_TRIGGER. Provides the
// same "write 1 to wake; read drains" semantics via the kqueue
// user-event ident space. Critical for the muxer_thread <- vCPU
// thread wake path.
