MAC address is changing on every incoming request on Ethernet Layer

Hi,

I just want to get mac address of my client. As you can see below, when I print the data struct of the Ethernet layer of incoming packet , I see that the MAC address is changing on every incoming request. (Just one client request, tested on different operating systems). What is the problem ?

```
// Get Mac Address
parserEth:=gopacket.NewDecodingLayerParser (
layers.LayerTypeEthernet,
ðLayer,
)
layerTE:=[]gopacket.LayerType{}
parserEth.DecodeLayers(packet.Data(), &layerTE)

for _, layerEth := range layerTE{
if(layerEth == layers.LayerTypeEthernet){
fmt.Printf("%+v\n", ethLayer)
}
}
```

{BaseLayer:{Contents:[69 0 0 52 239 148 0 0 55 6 180 187 91 191] Payload:[174 222 10 202 202 12 1 187 246 245 69 96 89 237 60 33 203 220 128 16 1 1 9 5 0 0 1 1 8 10 227 167 7 214 27 179 230 21]} SrcMAC:00:00:37:06:b4:bb DstMAC:45:00:00:34:ef:94 EthernetType:UnknownEthernetType Length:0}

{BaseLayer:{Contents:[69 0 0 64 0 0 64 0 63 6 192 157 10 202] Payload:[202 12 17 248 147 76 246 120 1 187 15 33 165 82 0 0 0 0 176 2 255 255 43 204 0 0 2 4 5 180 1 3 3 6 1 1 8 10 183 71 45 38 0 0 0 0 4 2 0 0]} SrcMAC:40:00:3f:06:c0:9d DstMAC:45:00:00:40:00:00 EthernetType:UnknownEthernetType Length:0}

{BaseLayer:{Contents:[69 0 0 60 0 0 64 0 53 6 203 161 17 248] Payload:[147 76 10 202 202 12 1 187 246 120 21 163 244 228 15 33 165 83 160 18 113 32 65 193 0 0 2 4 5 180 1 1 8 10 176 103 135 25 27 174 19 151 1 3 3 5]} SrcMAC:40:00:35:06:cb:a1 DstMAC:45:00:00:3c:00:00 EthernetType:UnknownEthernetType Length:0}

{BaseLayer:{Contents:[69 0 0 60 0 0 64 0 53 6 203 161 17 248] Payload:[147 76 10 202 202 12 1 187 246 120 21 163 244 228 15 33 165 83 160 18 113 32 65 193 0 0 2 4 5 180 1 1 8 10 176 103 135 25 27 174 19 151 1 3 3 5]} SrcMAC:40:00:35:06:cb:a1 DstMAC:45:00:00:3c:00:00 EthernetType:UnknownEthernetType Length:0}

{BaseLayer:{Contents:[69 0 0 52 0 0 64 0 63 6 192 169 10 202] Payload:[202 12 17 248 147 76 246 120 1 187 15 33 165 83 21 163 244 229 128 16 8 10 2 222 0 0 1 1 8 10 183 71 45 108 108 6 233 206]} SrcMAC:40:00:3f:06:c0:a9 DstMAC:45:00:00:34:00:00 EthernetType:UnknownEthernetType Length:0}