I'm including this library "ESP8266WiFi.h" at the top of my sketch. I can find documentation on WiFiServer.available() but didn't find for WiFi.connected() which is called in a server sketch after getting the client. Clearly it's a test whether (once? I believe) the client is connected or not (and hasn't been explicitly closed in the server's side). It may seem obvious but some documented info would be helpful though.