Improve lru_cache. Update test for it (#897)
Improve lru_cache. Update test for it (#897)


hjhjw1991/shadowsocks,ufownl/shadowsocks,kimw/shadowsocks,bwinhwang/shadowsocks,kimw/shadowsocks,xjz19901211/shadowsocks,catinred2/shadowsocks,catinred2/shadowsocks,falseen/shadowsocks,warmchang/shadowsocks,shell909090/shadowsocks,michalliu/shadowsocks,Rand01ph/shadowsocks,hjhjw1991/shadowsocks,CasparLi/shadowsocks,Rand01ph/shadowsocks,falseen/shadowsocks,CasparLi/shadowsocks,michalliu/shadowsocks,shell909090/shadowsocks,xjz19901211/shadowsocks,warmchang/shadowsocks,ufownl/shadowsocks,bwinhwang/shadowsocks