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: partial_events_merger.rs
    path of file: ./repos/vector/src/sources/kubernetes_logs
    
    the code of the file until where you have to start completion: #![deny(missing_docs)]

use bytes::BytesMut;
use futures::{Stream, StreamExt};
use std::collections::HashMap;
use std::time::{Duration, Instant};
use vector_lib::config::LogNamespace;
use vector_lib::lookup::OwnedTargetPath;
use vector_lib::stream::expiration_map::{map_with_expiration, Emitter};
use vrl::owned_value_path;

use crate::event;
use crate::event::{Event, LogEvent, Value};
use crate::sources::kubernetes_logs::transform_utils::get_message_path;

/// The key we use for `file` field.
const FILE_KEY: &str = "file";

const EXPIRATION_TIME: Duration = Duration::from_secs(30);

struct PartialEventMergeState {
    buc
    
    async fn merge_multiple_events_vector_namespace() {
        let mut e_1 = LogEvent::from(value!("test message 1"));
        e_1.insert(
            vrl::metadata_path!(super::super::Config::NAME, "_partial"),
            true,
        );
        e_1.insert(
            vrl::metadata_path!(super::super::Config::NAME, FILE_KEY),
            "foo1",
        );

        let mut e_2 = LogEvent::from(value!("test message 2"));
        e_2.insert(
            vrl::metadata_path!(super::super::Config::NAME, FILE_KEY),
            "foo1",
        );

        let input_stream = futures::stream::iter([e_1.into(), e_2.into()]);
        let output_stream = merge_partial_events(input_stream, LogNamespace::Vector);

        let output: Vec<Event> = output_stream.collect().await;
        assert_eq!(output.len(), 1);
        assert_eq!(
            output[0].as_log().get("."),
            Some(&value!("test message 1test message 2"))
        );
        assert_eq!(
            output[0].as_log().get("%kubernetes_logs.file"),
            Some(&value!("foo1"))
        );
    }