use try_future to block main thread
for rust style format
subpress output of apt-get
server support listening on multiple addrs and ports
Merge branch 'master' into dev
add example config
examples
add default trait
return an error struct
fixed useless copy
load balancer just need the server config
add table cipher for fallback
Merge branch 'dev'
graceful cmp
reconstructed and removed duplicated code, fixed bugs
omited unnecessary error message
improve error handling
fixed #3
fixed bugs, ready for udp implementation
fixed a ipv6 bug, modified config to contains real server ip