fix(network): implement fallback for sleep function in network connection handling

    end

    local ok_ffi, ffiutil = pcall(require, "ffi/util")

    local sleep_available = ok_ffi and ffiutil and type(ffiutil.sleep) == "function"

    local sleep_fn = nil

    if ok_ffi and ffiutil and type(ffiutil.sleep) == "function" then

        sleep_fn = ffiutil.sleep

    else

        -- Fallback for KOReader builds where ffi/util.sleep is unavailable.

        local ok_ffi_core, ffi = pcall(require, "ffi")

        if ok_ffi_core and ffi then

            pcall(function()

                ffi.cdef([[ unsigned int usleep(unsigned int usec); ]])

            end)

            if ffi.C and ffi.C.usleep then

                sleep_fn = function(seconds)

                    local usec = math.floor((tonumber(seconds) or 0) * 1000000)

                    if usec < 0 then usec = 0 end

                    ffi.C.usleep(usec)

                end

                self:logInfo("BookloreSync: Using ffi.usleep fallback for network wait")

            end

        end

    end

    local sleep_available = type(sleep_fn) == "function"

    local timeout = tonumber(self.network_connect_timeout_seconds) or DEFAULT_NETWORK_CONNECT_TIMEOUT_SECONDS

    if timeout < 1 then

        end

        if sleep_available then

            local ok_sleep, sleep_err = pcall(ffiutil.sleep, check_interval)

            local ok_sleep, sleep_err = pcall(sleep_fn, check_interval)

            if not ok_sleep then

                self:logWarn("BookloreSync: Sleep call failed while waiting for network:", tostring(sleep_err))

                break