run log:
====================
hello, world sync
hello, world sync
hello, world sync
hello, world sync
hello, world sync
Cost: 5512ms
====================
====================
send: world async
send: world async
send: world async
send: world async
send: world async
get: hello, world async
get: hello, world async
get: hello, world async
get: hello, world async
get: hello, world async
Cost: 1165ms
====================
====================
send: world async future
send: world async future
send: world async future
send: world async future
send: world async future
get: hello, world async
get: hello, world async
get: hello, world async
get: hello, world async
get: hello, world async
Cost: 1124ms
====================