Nabto Edge uses
Futures to manage return values and completion of asynchronous API-functions; a
future resolves once such function has completed. Additionally, the Listener API supports
asynchronous functions that are expected to be invoked recurringly (see the Futures
Guide for details).
Listeners are created and freed through this general API. Once created, a listener is initialized for use with a specific purpose, e.g. to listen for incoming coap requests, incoming stream requests or general device events.