NetworkManagementService
EthernetTracker
18:handleAsyncChannelHalfConnect
25: handleRegisterNetworkAgent
10：new
SystemServer
7：onBootPhase
17：nfi.asyncChannel.connect
14：registerNetworkFactory在ConnectivityService中注册AsyncChannel单向通信，提供CS到ENF的通信，包括网络有效性，及自动连接，主动断网等。
Netd
12: systemReady
28: CMD_CHANNEL_FULLY_CONNECTED
3: registerUnsolicitedEventListener注册Netd的Listener，底层有事件上报会通过该Listener通知上层服务
28: CMD_CHANNEL_FULL_CONNECTION
8：start
1: startOtherServices
27: handleAsyncChannelHalfConnect
16: registerObserver：注册监听来自NMS收到底层的事件，如果interface的add/removed等
23: new
EthernetService
system_server进程
9: new
21: needNetworkFor
5：new
20: handleAddRequest
4: new
26: nai.asyncChannel.connect
19: CMD_REQUEST_NETWORK
2: create
6: new
22: startNetwork
24: registerNetworkAgent
13：register
11: systemReady
ConnectivityService
NetworkAgent
15：start
EthernetServiceImp
EthernetNetworkFactory
