You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: routing.rs
    path of file: ./repos/rustful/src/handler
    
    the code of the file until where you have to start completion: //!Routing related traits and types.

use std::collections::HashMap;
use std::iter::{Iterator, FlatMap};
use std::slice::Split;
use std::ops::Deref;

use context::MaybeUtf8Owned;

///A segmented route.
pub trait Route<'a> {
    ///An iterator over route segments.
    type Segments: Iterator<Item=&'a [u8]>;

    ///Create a route segment iterator. The iterator is expected to return
    ///None for a root path (`/`).
    ///
    ///```rust
    ///# use rustful::handler::routing::Route;
    //
    
    pub fn variables(&self, names: &[MaybeUtf8Owned]) -> HashMap<MaybeUtf8Owned, MaybeUtf8Owned> {
        let values = self.route.iter().zip(self.variables.iter()).filter_map(|(v, keep)| {
            if let Some(index) = *keep {
                Some((index, *v))
            } else {
                None
            }
        });

        let mut var_map = HashMap::<MaybeUtf8Owned, MaybeUtf8Owned>::with_capacity(names.len());
        for (name, value) in VariableIter::new(names, values) {
            var_map.insert(name, value);
        }

        var_map
    }