Merge pull request #40 from alexcrichton/update-reamde

Update README slightly

README.md

@@ -6,8 +6,31 @@
 
 Rust crate for waiting on a `Child` process with a timeout specified.
 
-```toml
-# Cargo.toml
-[dependencies]
-wait-timeout = "0.1.5"
+```sh
+$ cargo add wait-timeout
+```
+
+Example:
+
+```rust
+use std::io;
+use std::process::Command;
+use std::time::{Duration, Instant};
+use wait_timeout::ChildExt;
+
+fn main() -> io::Result<()> {
+    let mut child = Command::new("sleep").arg("100").spawn()?;
+
+    let start = Instant::now();
+    assert!(child.wait_timeout(Duration::from_millis(100))?.is_none());
+    assert!(start.elapsed() > Duration::from_millis(100));
+
+    child.kill()?;
+
+    let start = Instant::now();
+    assert!(child.wait_timeout(Duration::from_millis(100))?.is_some());
+    assert!(start.elapsed() < Duration::from_millis(100));
+
+    Ok(())
+}
 ```