Hi,

Currently ESP8266WebServer::client() returns a WiFiClient by value, which forbids passing the result directly to a function taking a Client&.

For example, it causes a compilation error with ArduinoJson:

serializeJson(doc, server.client());

Because serializeJson() takes a Print&, the line above produces the following error:

no instance of overloaded function "serializeJson" matches the argument list -- argument types are: (ArduinoJson6141_0000010::StaticJsonDocument<768U>, WiFiServer::ClientType)

To fix this problem, ESP8266WebServer::client() must return a reference (and not a copy), just as HTTPClient::getStream() does.

(see also this question on StackOverflow)

Best regards,
Benoit