Golang process config synchronization using etcd
migrate from 17media/config and update etcdclient to v3
deprecates 17media/go-etcd
note that we ignore errors that files are too large to push (limitation for server side: 1.5 MiB, client side: 2 MiB), because they are not etcd meant to maintain
see https://etcd.io/docs/v3.3/upgrades/upgrade_3_2/#changed-maximum-request-size-limits-3210 (old change log),
for pusher, only push modified files as key to etcd, currently we push all keys in repo
for clientv3, we need to check behavior when etcd is down (should reconnect?)
documentation
check stats implementation