Add doc example for `std::io::repeat`.

diff --git a/src/libstd/io/util.rs b/src/libstd/io/util.rs
index 2815c0163d68a86e448dc50f459b0c00663c4e21..a8683723cad667a4137cccb7119bed401e2e393d 100644 (file)
--- a/src/libstd/io/util.rs
+++ b/src/libstd/io/util.rs
@@ -113,6 +113,16 @@ pub struct Repeat { byte: u8 }
 ///
 /// All reads from this reader will succeed by filling the specified buffer with
 /// the given byte.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = [0; 3];
+/// io::repeat(0b101).read_exact(&mut buffer).unwrap();
+/// assert_eq!(buffer, [0b101, 0b101, 0b101]);
+/// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 pub fn repeat(byte: u8) -> Repeat { Repeat { byte: byte } }