A protothread is a memory-efficient programming abstraction that shares features of both multi-threading and event-driven programming to attain a low memory overhead of each protothread.
Decomposing services into a set of stages also enables modularity and code reuse, as well as the development of debugging tools for complex event-driven applications.
The usage model is typical of an event-driven architecture, in which the application performs a setup and then receives callbacks as events occur (fig 6).
