Sming Framework API
Sming - Open Source framework for high efficiency WiFi SoC ESP8266 native development with C++ language.
It will communicate well to an Arduino-based unit as well, so it's not for only Maple-to-Maple communication.
Write this sketch to two different nodes, connect the role_pin to ground on one. The ping node sends the current time to the pong node, which responds by sending the value back. The ping node can then see how long the whole cycle took.