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: tcp.rs
    path of file: ./repos/firecracker/src/vmm/src/dumbo/pdu
    
    the code of the file until where you have to start completion: // Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0

//! Contains support for parsing and writing TCP seg
    
    pub fn set_header_len_rsvd_ns(&mut self, header_len: u8, ns: bool) -> &mut Self {
        let mut value = header_len << 2;
        if ns {
            value |= 1;
        }
        self.bytes[DATAOFF_RSVD_NS_OFFSET] = value;
        self
    }