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: meta_storage.rs
    path of file: ./repos/tikv/components/test_pd/src/mocker
    
    the code of the file until where you have to start completion: // Copyright 2023 TiKV Project Authors. Licensed under Apache-2.0.

use std::sync::{Arc, Mutex};

use futures::{executor::block_on, SinkExt, StreamExt};
use grpcio::{RpcStatus, RpcStatusCode};
use kvproto
    
    fn meta_store_put(&self, mut req: mpb::PutRequest) -> Option<super::Result<mpb::PutResponse>> {
        if let Err(err) = check_header(req.get_header()) {
            return Some(Err(err));
        }

        let mut store = self.store.lock().unwrap();
        block_on(store.set(KeyValue(MetaKey(req.take_key()), req.take_value()))).unwrap();
        Some(Ok(Default::default()))
    }