InstanceResource#cancelLease()
initScheduledTasks()
HTTP请求
shutdown()
cancel()
sendHeartBeat()
register()
InstanceResource#renewLease()
EvictionTask
eureka客户端与服务端调用链路图
euerka服务端
DiscoveryClient
LeaseManager
ApplicationResource/InstanceResource
heartbeat定时任务HeartbeatThread
ApplicationResource#addInstance()
EurekaHttpClient
evict()
renew()
euerka客户端
