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: local_drain.rs
    path of file: ./repos/sozu/lib/src/metrics
    
    the code of the file until where you have to start completion: #![allow(dead_code)]
use std::{
    collectio
    
    fn receive_and_yield_cluster_metrics() {
        let mut local_drain = LocalDrain::new("prefix".to_string());
        local_drain.receive_metric(
            "http_errors",
            Some("test-cluster"),
            None,
            MetricValue::Count(1),
        );
        local_drain.receive_metric(
            "http_errors",
            Some("test-cluster"),
            None,
            MetricValue::Count(1),
        );

        let mut map = BTreeMap::new();
        map.insert(
            "http_errors".to_string(),
            FilteredMetrics {
                inner: Some(Inner::Count(2)),
            },
        );
        let expected_cluster_metrics = ClusterMetrics {
            cluster: map,
            backends: vec![],
        };

        let returned_cluster_metrics = local_drain
            .metrics_of_one_cluster("test-cluster", &["http_errors".to_string()].to_vec())
            .expect("could not query metrics for this cluster");

        assert_eq!(expected_cluster_metrics, returned_cluster_metrics);
    }