Merge pull request #2 from xiangli-cmu/master

fix(receiver.go) create a new message in handler
Merge pull request #3 from xiangli-cmu/master

feat(sender.go) finish a draft sender with simple test
add a simple bench for send/receiver, small modification to send_test
gofmt
a little modification to make it easier to read
change start() to Start() and Start() to GoStart()
Merge pull request #4 from yifan-gu/master

add a simple bench for send/receiver, small modification to send_test
change addr string to addr struct in Receiver{}
Merge pull request #5 from yifan-gu/master

change addr string to addr struct in Receiver{}
feat(receiver.go) add sendto