Asynchrony and concurrency are distinct concepts in programming, with asynchrony allowing tasks to run out of order while remaining correct, and concurrency enabling multiple tasks to progress simultaneously. The article argues that misunderstanding these terms has led to unnecessary complexity in programming ecosystems, particularly in libraries and user experiences. It highlights how Zig’s approach to asynchronous I/O allows for single-threaded blocking execution without forcing users into asynchronous paradigms.

Zig has introduced a new asynchronous I/O interface that allows developers to specify the concrete I/O implementation, enhancing code reusability and performance. This design decouples async/await from the execution model, enabling better concurrency management and supporting various I/O implementations, including blocking and event-driven models. The article discusses the implications of this change through code examples and outlines future implementations planned for Zig's standard library.

The article discusses the author's journey in adopting the Zig programming language for network programming, highlighting the development of "Zio," an asynchronous I/O and concurrency library for Zig. The author contrasts their experiences with previous languages like C++ and Go, emphasizing Zig's capabilities in creating efficient and scalable network applications. Zio allows for easier asynchronous programming through stackful coroutines, achieving high performance in both single-threaded and multi-threaded environments.