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: media.rs
    path of file: ./repos/matrix-rust-sdk/crates/matrix-sdk-base/src
    
    the code of the file until where you have to start completion: //! Common types for [media content](https://matrix.org/docs/spec/client_server/r0.6.1#id66).

use ruma::{
    api::client::media::get_content_thumbnail::v3::Method,
    events::{
        room::{
            message::{
                AudioMessageEventContent, FileMessageEventContent, ImageMessageEventContent,
                LocationMessageEventContent, VideoMessageEventContent,
            },
            MediaSource,
        },
        sticker::StickerEventContent,
    },
    MxcUri, UInt,
};

const UNIQUE_SEPARATOR: &str = "_";

/// A trait to uniquely identify values of the same type.
pub trait UniqueKey {
    /// A string that uniquely identifies `Self` compared to other values of
    /// the same type.
    fn unique_key(&self) -> String;
}

/// The requested format of a media file.
#[derive(Clone, Debug)]
pub enum MediaFormat {
    /// The file that was uploaded.
  
    
    fn test_media_request_url() {
        let mxc_uri = mxc_uri!("mxc://homeserver/media");

        let plain = MediaRequest {
            source: MediaSource::Plain(mxc_uri.to_owned()),
            format: MediaFormat::File,
        };

        assert_eq!(plain.uri(), mxc_uri);

        let file = MediaRequest {
            source: MediaSource::Encrypted(Box::new(
                serde_json::from_value(json!({
                    "url": mxc_uri,
                    "key": {
                        "kty": "oct",
                        "key_ops": ["encrypt", "decrypt"],
                        "alg": "A256CTR",
                        "k": "b50ACIv6LMn9AfMCFD1POJI_UAFWIclxAN1kWrEO2X8",
                        "ext": true,
                    },
                    "iv": "AK1wyzigZtQAAAABAAAAKK",
                    "hashes": {
                        "sha256": "foobar",
                    },
                    "v": "v2",
                }))
                .unwrap(),
            )),
            format: MediaFormat::File,
        };

        assert_eq!(file.uri(), mxc_uri);
    }