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: reader.rs
    path of file: ./repos/risingwave/src/connector/src/source/filesystem/s3/source
    
    the code of the file until where you have to start completion: // Copyright 2024 RisingWave Labs
//
// 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::collections::HashMap;
use std::pin::pin;

use anyhow::anyhow;
use async_trait::async_trait;
use aws_sdk_s3::client as s3_client;
use aws_sdk_s3::operation::get_object::GetObjectError;
use aws_smithy_http::futures_stream_adapter::FuturesStreamCompatByteStream;
use aws_smithy_runtime_api::client::result::SdkError;
use aws_smithy_types::body::SdkBody
    
    async fn test_s3_split_reader() {
        let props: S3Properties = S3PropertiesCommon {
            region_name: "ap-southeast-1".to_owned(),
            bucket_name: "mingchao-s3-source".to_owned(),
            match_pattern: None,
            access: None,
            secret: None,
            endpoint_url: None,
        }
        .into();
        let mut enumerator =
            S3SplitEnumerator::new(props.clone(), SourceEnumeratorContext::default().into())
                .await
                .unwrap();
        let splits = enumerator.list_splits().await.unwrap();
        println!("splits {:?}", splits);

        let descs = vec![
            SourceColumnDesc::simple("id", DataType::Int64, 1.into()),
            SourceColumnDesc::simple("name", DataType::Varchar, 2.into()),
            SourceColumnDesc::simple("age", DataType::Int32, 3.into()),
        ];

        let csv_config = CsvProperties {
            delimiter: b',',
            has_header: true,
        };

        let config = ParserConfig {
            common: CommonParserConfig { rw_columns: descs },
            specific: SpecificParserConfig {
                key_encoding_config: None,
                encoding_config: EncodingProperties::Csv(csv_config),
                protocol_config: ProtocolProperties::Plain,
            },
        };

        let reader = S3FileReader::new(props, splits, config, Default::default(), None)
            .await
            .unwrap();

        let msg_stream = reader.into_chunk_stream();
        #[for_await]
        for msg in msg_stream {
            println!("msg {:?}", msg);
        }
    }