select(.....,0.5), it will be too slow ....? #1

he ,buddy, I read you code, it's good . but I have two question:

1, In recvall fun,you use select(.....,0.5) , so 0.5 s will be too slow for network, why don't set socket to be nonblocking??

2, when finish one time request and response ,you just close both socket , will it be too rush? I mean some connections will be used again in keep-alive ...