This is a modified version of the WiFi library from the Arduino Espressif32 Framework. The original code is from the 2.0.7 version of that framework.
It adds a new WiFiClient::canWrite() method. That method can be used to determine if the TCP connection is ready to receive new data without blocking. FluidNC needs that feature to determine if a new status report can be sent over a WebSocket without stalling the system. This is used in conjunction with a modified version of the arduinoWebSockets library