public:

io_kqueue_backend();

~io_kqueue_backend() override;

std::uint64_t event_count() const;

std::uint64_t buffered_eof_events() const;

std::uint64_t successful_receipts() const;

std::uint64_t failed_receipts() const;

private:

void rearm_locked(registration& record, std::uint32_t mask, std::vector<struct kevent>& changes);

void apply_changes_locked(const std::vector<struct kevent>& changes);

void process_event(const struct kevent& event);

static bool valid_event(const registration& record, const struct kevent& event);

static bool valid_receipt(const struct kevent& change, const struct kevent& receipt);

static bool buffered_read_eof(const struct kevent& event);

std::optional<std::chrono::steady_clock::time_point> reconcile_locked() override;

void dispatch_event(std::uint64_t token, std::uint32_t events);

void run_loop() override;

static std::atomic<std::uint64_t> all_events_;

static std::atomic<std::uint64_t> all_waits_;

std::uint64_t events_ = 0;

std::uint64_t buffered_eof_ = 0;

std::uint64_t receipts_ = 0;

std::uint64_t failed_receipts_ = 0;

using kevent_call = int (*)(int, const struct kevent*, int, struct kevent*, int, const struct timespec*);

kevent_call kevent_ = &::kevent;

int kqueue_ = -1;