Secure async TCP sockets with [sock] and [libtls].
stls.client_stcp(tcp, servername, opt) -> cstcp
create a secure socket for a client
stls.server_stcp(tcp, opt) -> sstcp
create a secure socket for a server
cstcp:recv()
same semantics as tcp:recv()
cstcp:send()
same semantics as tcp:send()
cstcp:recvn()
same semantics as tcp:recvn()
cstcp:recvall()
same semantics as tcp:recvall()
cstcp:recvall_read()
same semantics as tcp:recvall_read()
sstcp:accept() -> cstcp
accept a client connection
cstcp:shutdown('r'|'w'|'rw')
calls self.tcp:shutdown()
cstcp:close()
close client socket
sstcp:close()
close server socket