//! enum Version { Version1, Version2 }
//!
//! fn parse_version(header: &[u8]) -> Result<Version, &'static str> {
-//! if header.len() < 1 {
-//! return Err("invalid header length");
-//! }
-//! match header[0] {
-//! 1 => Ok(Version::Version1),
-//! 2 => Ok(Version::Version2),
-//! _ => Err("invalid version")
+//! match header.get(0) {
+//! None => Err("invalid header length"),
+//! Some(&1) => Ok(Version::Version1),
+//! Some(&2) => Ok(Version::Version2),
+//! Some(_) => Err("invalid version")
//! }
//! }
//!