Unified Async/Sync Function Execution

run-async is a utility method designed to normalize the execution of functions that can operate synchronously, asynchronously via a `this.async()` callback, or by returning a Promise. This library is particularly useful for authors of middleware or plugins that need to accept user-provided functions with varying asynchronous patterns, ensuring a consistent execution flow. The current stable version is 4.0.6, and the project demonstrates an active maintenance cadence, addressing dependency issues and enhancing functionality across major versions. A key differentiator is its ability to abstract away the underlying async mechanism, providing a single interface, and its current status as a dependency-free package since version 2.4.1, which improves reliability and reduces supply chain risks.