server_conn_test.go bug修改，会导致conn为nil，导致panic
server_conn_test.go bug修改，会导致conn为nil，导致panic

zhouhui8915/go-engine.io,DisruptiveMind/go-engine.io,zhouhui8915/go-engine.io,DisruptiveMind/go-engine.io,zhouhui8915/go-engine.io,DisruptiveMind/go-engine.io