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: snapshot.rs
    path of file: ./repos/materialize/src/storage/src/source/postgres
    
    the code of the file until where you have to start completion: // Copyright Materialize, Inc. and contributors. All rights reserved.
//
// Use of this software is governed by the Business Source License
// included in the LICENSE file.
//
// As of the Change Date specified in that file, in accordance with
// the Business Source License, use of this software will be governed
// by the Apache License, Version 2.0.

//! Renders the table snapshot side of the [`PostgresSourceConnection`] ingestion dataflow.
//!
//! # Snapshot reading
//!
//! Depending on the resumption LSNs the table reader d
    
fn decode_copy_row(data: &[u8], col_len: usize, row: &mut Row) -> Result<(), DefiniteError> {
    let mut packer = row.packer();
    let row_parser = mz_pgcopy::CopyTextFormatParser::new(data, b'\t', "\\N");
    let mut column_iter = row_parser.iter_raw_truncating(col_len);
    for _ in 0..col_len {
        let value = match column_iter.next() {
            Some(Ok(value)) => value,
            Some(Err(_)) => return Err(DefiniteError::InvalidCopyInput),
            None => return Err(DefiniteError::MissingColumn),
        };
        let datum = value.map(super::decode_utf8_text).transpose()?;
        packer.push(datum.unwrap_or(Datum::Null));
    }
    Ok(())
}