Bug fixes:
- fix incorrect session type in netpacket.rpcpack
- fix incorrect call of lua_gc
- handle socket close event in send_msg_tcp/send_msg_udp
New features:
- add cluster module to provide some help for cluster networking
- use parameters instead of environment variables to override startup variables (#984308b)
- add examples for timer,socket,RPC,HTTP,WebSocket
- refine core.timeout for a large number of timer events(delay creating a task for timer event can reduce the memory usage to 30% of the original)
- crypto.base64encode support URL safe code and add crypto.sha256, crypto.digestsign, crypto.digestverify
- TLS support SNI, ALPN
- support HTTP2
- refine patch(more flexible, more powerful)
- more monitor data(timer event info, more memory info)