Fix missing vendor dir

vendor/github.com/shirou/gopsutil/mem/mem_darwin.go

@@ -0,0 +1,70 @@
+// +build darwin
+
+package mem
+
+import (
+	"context"
+	"fmt"
+	"unsafe"
+
+	"github.com/shirou/gopsutil/internal/common"
+	"golang.org/x/sys/unix"
+)
+
+func getHwMemsize() (uint64, error) {
+	total, err := unix.SysctlUint64("hw.memsize")
+	if err != nil {
+		return 0, err
+	}
+	return total, nil
+}
+
+// xsw_usage in sys/sysctl.h
+type swapUsage struct {
+	Total     uint64
+	Avail     uint64
+	Used      uint64
+	Pagesize  int32
+	Encrypted bool
+}
+
+// SwapMemory returns swapinfo.
+func SwapMemory() (*SwapMemoryStat, error) {
+	return SwapMemoryWithContext(context.Background())
+}
+
+func SwapMemoryWithContext(ctx context.Context) (*SwapMemoryStat, error) {
+	// https://github.com/yanllearnn/go-osstat/blob/ae8a279d26f52ec946a03698c7f50a26cfb427e3/memory/memory_darwin.go
+	var ret *SwapMemoryStat
+
+	value, err := unix.SysctlRaw("vm.swapusage")
+	if err != nil {
+		return ret, err
+	}
+	if len(value) != 32 {
+		return ret, fmt.Errorf("unexpected output of sysctl vm.swapusage: %v (len: %d)", value, len(value))
+	}
+	swap := (*swapUsage)(unsafe.Pointer(&value[0]))
+
+	u := float64(0)
+	if swap.Total != 0 {
+		u = ((float64(swap.Total) - float64(swap.Avail)) / float64(swap.Total)) * 100.0
+	}
+
+	ret = &SwapMemoryStat{
+		Total:       swap.Total,
+		Used:        swap.Used,
+		Free:        swap.Avail,
+		UsedPercent: u,
+	}
+
+	return ret, nil
+}
+
+func SwapDevices() ([]*SwapDevice, error) {
+	return SwapDevicesWithContext(context.Background())
+}
+
+func SwapDevicesWithContext(ctx context.Context) ([]*SwapDevice, error) {
+	return nil, common.ErrNotImplementedError
+}