//! A capability-based API modeled after `async_std`.
//!
//! This corresponds to [`async_std`].
//!
//! Capability-based APIs represent access to external resources as
//! objects which can be passed around between different parts of a
//! program.
//!
//! Two notable features are the [`Dir`] and [`Catalog`] types:
//! - `Dir` represents an open directory in a filesystem. Instead of
//! opening files by absolute paths or paths relative to the current
//! working directory, files are opened via paths relative to a
//! `Dir`. The concepts of a process-wide "current working directory"
//! and a single global filesystem namespace are de-emphasized.
//! - `Catalog` represents a set of network addresses. Instead of
//! allowing applications to request access to any address and then
//! applying process-wide filtering rules, filtering rules are
//! built into catalogs which may be passed through the program.
//!
//! On WASI, use of this library closely reflects the underlying system
//! API, so it avoids compatibility layers.
//!
//! [`async_std`]: https://docs.rs/async-std/latest/async_std/
//! [`Dir`]: fs/struct.Dir.html
//! [`Catalog`]: net/struct.Catalog.html
// TODO: When more things are implemented, remove these.