The article introduces a new series, "Zed Decoded," which explores the construction, technologies, and challenges of developing the Zed application, focusing particularly on its use of async Rust. The author collaborates with colleagues to delve into async Rust's implementation in Zed, discussing the application's high-performance capabilities. The article highlights the advantages of using macOS's Grand Central Dispatch (GCD) as the runtime for asynchronous code execution, diverging from traditional runtimes like tokio or smol. It explains the importance of maintaining responsiveness by distinguishing between foreground and background executors to prevent blocking the main thread, a critical aspect for UI applications. The author also touches on the collaborative effort in maintaining Zed's performance and responsiveness, providing examples from the codebase that illustrate how tasks are managed across different threads to ensure efficient operation. For further insights, the article references a companion video and future posts that will explore Zed's data structures and testing methodologies in more detail.