Every time use Server functionality, we need to include header file"WiFi.h".
WiFiServer(uint16_t port=80, uint8_t max_clients=4): create a TCP Server.
port: ports of Server; range from 0 to 65535 with the default number as 80.
max_clients: maximum number of clients with default number as 4.
begin(port): start the TCP Server.
port: ports of Server; range from 0 to 65535 with the default number as 0.
setNoDelay(bool nodelay): whether to turn off the delay sending functionality.
nodelay: true stands for forbidden Nagle algorithm.
close(): close tcp connection.
stop(): stop tcp connection.