change net hardware adress to string.

net.go

@@ -17,7 +17,6 @@ type NetIOCountersStat struct {
 	Dropout     uint64 `json:"dropout"`      // total number of outgoing packets which were dropped (always 0 on OSX and BSD)
 }
 
-
 // Addr is implemented compatibility to psutil
 type Addr struct {
 	IP   string `json:"ip"`
@@ -42,7 +41,7 @@ type NetInterfaceAddr struct {
 type NetInterfaceStat struct {
 	MTU          int                `json:"mtu"`          // maximum transmission unit
 	Name         string             `json:"name"`         // e.g., "en0", "lo0", "eth0.100"
-	HardwareAddr []byte     `json:"hardwareaddr"` // IEEE MAC-48, EUI-48 and EUI-64 form
+	HardwareAddr string             `json:"hardwareaddr"` // IEEE MAC-48, EUI-48 and EUI-64 form
 	Flags        []string           `json:"flags"`        // e.g., FlagUp, FlagLoopback, FlagMulticast
 	Addrs        []NetInterfaceAddr `json:"addrs"`
 }
@@ -72,7 +71,6 @@ func (n NetInterfaceAddr) String() string{
 	return string(s)
 }
 
-
 func NetInterfaces() ([]NetInterfaceStat, error) {
 	is, err := net.Interfaces()
 	if err != nil {
@@ -101,7 +99,7 @@ func NetInterfaces() ([]NetInterfaceStat, error) {
 		r := NetInterfaceStat{
 			Name:         ifi.Name,
 			MTU:          ifi.MTU,
-			HardwareAddr: ifi.HardwareAddr,
+			HardwareAddr: ifi.HardwareAddr.String(),
 			Flags:        flags,
 		}
 		addrs, err := ifi.Addrs()