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: queue.rs
    path of file: ./repos/matrix-rust-sdk/crates/matrix-sdk-ui/tests/integration/timeline
    
    the code of the file until where you have to start completion: // Copyright 2023 The Matrix.org Foundation C.I.C.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use std::{sync::Arc, time::Duration};

use assert_matches::assert_matches;
use assert_matches2::assert_let;
use eyeball_im::VectorDiff;
use futures_util::StreamExt;
use matrix_sdk::{config::SyncSettings, test_utils::logged_in_client_with_server};
use matrix_sdk_test::{async_test, EventBuilder, JoinedRoomBuilder, SyncResponseBuilder, ALICE};
use matrix_sdk_ui::timeline::{EventItemOrigin, EventSendState, RoomExt};
use ruma::{events::room::message::RoomMessageEventContent, room_id};
use serde_json::json;
use stream_assert::{assert_next_matches, assert_pending};
use tokio::time::sleep;
use wiremock::{
    matchers::{body_string_contains, method, path_regex},
    Mock, ResponseTemplate,
};

use crate::{mock_encryption_state, mock_sync};

#[async_test]
async fn test_message_order() {
    let room_id = room_id!("!a98sd12bjh:example.org");
    let (client, server) = logged_in_client_with_server().await;
    let sync_settings = SyncSettings::new().timeout(Duration::from_millis(3000));

    let mut ev_builder = SyncResponseBuilder::new();
    ev_builder.add_joined_room(JoinedRoomBuilder::new(room_id));

    mock_sync(&server, ev_builder.build_json_sync_response(), None).await;
    let _response = client.sync_once(sync_settings.clone()).await.unwrap();
    server.reset().await;

    mock_encryption_state(&server, false).await;

    let room = client.get_room(room_id).unwrap();
    let timeline = Arc::new(room.timeline().await.unwrap());
    let (_, mut timeline_stream) =
        timeline.subscribe_filter_map(|item| item.as_event().cloned()).await;

    // Response for first message takes 200ms to respond
    Mock::given(method("PUT"))
        .and(path_regex(r"^/_matrix/client/r0/rooms/.*/send/.*"))
        .and(body_string_contains("First!"))
        .respond_with(
            ResponseTemplate::new(200)
                .set_body_json(&json!({ "event_id": "$PyHxV5mYzjetBUT3qZq7V95GOzxb02EP" }))
                .set_delay(Duration::from_millis(200)),
        )
        .mount(&server)
        .await;

    // Response 
    
async fn test_clear_with_echoes() {
    let room_id = room_id!("!a98sd12bjh:example.org");
    let (client, server) = logged_in_client_with_server().await;
    let sync_settings = SyncSettings::new().timeout(Duration::from_millis(3000));

    let event_builder = EventBuilder::new();
    let mut sync_builder = SyncResponseBuilder::new();
    sync_builder.add_joined_room(JoinedRoomBuilder::new(room_id));

    mock_sync(&server, sync_builder.build_json_sync_response(), None).await;
    let _response = client.sync_once(sync_settings.clone()).await.unwrap();
    server.reset().await;

    mock_encryption_state(&server, false).await;

    let room = client.get_room(room_id).unwrap();
    let timeline = room.timeline().await.unwrap();

    // Send a message without mocking the server response.
    {
        let (_, mut timeline_stream) = timeline.subscribe().await;

        timeline.send(RoomMessageEventContent::text_plain("Send failure").into()).await;

        // Wait for the first message to fail. Don't use time, but listen for the first
        // timeline item diff to get back signalling the error.
        let _day_divider = timeline_stream.next().await;
        let _local_echo = timeline_stream.next().await;
        let _local_echo_replaced_with_failure = timeline_stream.next().await;
    }

    // Next message will take "forever" to send.
    Mock::given(method("PUT"))
        .and(path_regex(r"^/_matrix/client/r0/rooms/.*/send/.*"))
        .respond_with(
            ResponseTemplate::new(200)
                .set_body_json(&json!({ "event_id": "$PyHxV5mYzjetBUT3qZq7V95GOzxb02EP" }))
                .set_delay(Duration::from_secs(3600)),
        )
        .mount(&server)
        .await;

    // (this one)
    timeline.send(RoomMessageEventContent::text_plain("Pending").into()).await;

    // Another message comes in.
    sync_builder.add_joined_room(JoinedRoomBuilder::new(room_id).add_timeline_event(
        event_builder.make_sync_message_event(
            &ALICE,
            RoomMessageEventContent::text_plain("another message"),
        ),
    ));
    mock_sync(&server, sync_builder.build_json_sync_response(), None).await;
    client.sync_once(sync_settings.clone()).await.unwrap();

    // At this point, there should be three timeline items:
    let timeline_items = timeline.items().await;
    let event_items: Vec<_> = timeline_items.iter().filter_map(|item| item.as_event()).collect();

    assert_eq!(event_items.len(), 3);
    // The message that failed to send.
    assert_matches!(event_items[0].send_state(), Some(EventSendState::SendingFailed { .. }));
    // The message that came in from sync.
    assert_matches!(event_items[1].origin(), Some(EventItemOrigin::Sync));
    // The message that is still pending.
    assert_matches!(event_items[2].send_state(), Some(EventSendState::NotSentYet));

    // When we clear the timeline now,
    timeline.clear().await;

    // â€¦ the two local messages should remain.
    let timeline_items = timeline.items().await;
    let event_items: Vec<_> = timeline_items.iter().filter_map(|item| item.as_event()).collect();

    assert_eq!(event_items.len(), 2);
    assert_matches!(event_items[0].send_state(), Some(EventSendState::SendingFailed { .. }));
    assert_matches!(event_items[1].send_state(), Some(EventSendState::NotSentYet));
}