+//! # netwatcher
+//!
+//! `netwatcher` is a cross-platform library for enumerating network interfaces and their
+//! IP addresses, featuring the ability to watch for changes to those interfaces
+//! _efficiently_. It uses platform-specific methods to detect when interface changes
+//! have occurred instead of polling, which means that you find out about changes more
+//! quickly and there is no CPU or wakeup overhead when nothing is happening.
+//!
+//! ## List example
+//!
+//! ```
+//! /// Returns a HashMap from ifindex (a `u32`) to an `Interface` struct
+//! let interfaces = netwatcher::list_interfaces().unwrap();
+//! for i in interfaces.values() {
+//! println!("interface {} has {} IPs", i.name, i.ips.len());
+//! }
+//! ```
+//!
+//! ## Watch example
+//!
+//! ```
+//! let handle = netwatcher::watch_interfaces(|update| {
+//! // This callback will fire once immediately with the existing state
+//!
+//! // Update includes the latest snapshot of all interfaces
+//! println!("Current interface map: {:#?}", update.interfaces);
+//!
+//! // The `UpdateDiff` describes changes since previous callback
+//! // You can choose whether to use the snapshot, diff, or both
+//! println!("ifindexes added: {:?}", update.diff.added);
+//! println!("ifindexes removed: {:?}", update.diff.removed);
+//! for (ifindex, if_diff) in update.diff.modified {
+//! println!("Interface index {} has changed", ifindex);
+//! println!("Added IPs: {:?}", if_diff.addrs_added);
+//! println!("Removed IPs: {:?}", if_diff.addrs_removed);
+//! }
+//! });
+//! // keep `handle` alive as long as you want callbacks
+//! // ...
+//! drop(handle);
+//! ```
+
use std::{
collections::{HashMap, HashSet},
net::{IpAddr, Ipv4Addr, Ipv6Addr},