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: shape_tag.rs
    path of file: ./repos/aws-sdk-rust/sdk/redshift/src/protocol_serde
    
    the code of the file until where you have to start completion: // Code generated by software.amazon.smithy.rust.codegen.smithy-rs. DO NOT EDIT.
#[allow(unused_mut)]
pub fn ser_tag(
    mut writer: ::aws_smithy_query::QueryValueWriter,
    input: &crate::types::Tag,
) -> Result<(), ::aws_smithy_types::error::operation::SerializationError> {
    #[allow(unused_mut)]
    let mut scope_1 = writer.prefix("Key");
    if let Some(var_2) = &input.key {
        scope_1.string(var_2);
    }
    #[allow(unused_mut)]
    let mut scope_3 = writer.prefix("Value");
    if let Some(var_4) = &input.value {
        scope_3.string(var_4);
    }
    Ok(())
}

#[allow(clippy::needless_question_mark)]
pub fn de_tag(decoder: &mut ::aws_smithy_xml::decode::ScopedDecoder) -> Result<crate::types::Tag, ::aws_smithy_xml::decode::XmlDecodeError> {
    #[allow(unused_mut)]
    let mut builder = crate::types::Tag::builder();
    while let Some(mut tag) = decoder.next_tag() {
        match tag.start_el() {
            s if s.matches("Key") /* Key com.amazonaws.redshift#Tag$Key */ =>  {
                let var_5 =
                    Some(
                        Result::<::std::string::String, ::aws_smithy_xml::decode::XmlDecodeError>::Ok(
                            ::aws_smithy_xml::decode::try_data(&mut tag)?.as_ref()
                            .into()
    
pub fn de_tag(decoder: &mut ::aws_smithy_xml::decode::ScopedDecoder) -> Result<crate::types::Tag, ::aws_smithy_xml::decode::XmlDecodeError> {
    #[allow(unused_mut)]
    let mut builder = crate::types::Tag::builder();
    while let Some(mut tag) = decoder.next_tag() {
        match tag.start_el() {
            s if s.matches("Key") /* Key com.amazonaws.redshift#Tag$Key */ =>  {
                let var_5 =
                    Some(
                        Result::<::std::string::String, ::aws_smithy_xml::decode::XmlDecodeError>::Ok(
                            ::aws_smithy_xml::decode::try_data(&mut tag)?.as_ref()
                            .into()
                        )
                        ?
                    )
                ;
                builder = builder.set_key(var_5);
            }
            ,
            s if s.matches("Value") /* Value com.amazonaws.redshift#Tag$Value */ =>  {
                let var_6 =
                    Some(
                        Result::<::std::string::String, ::aws_smithy_xml::decode::XmlDecodeError>::Ok(
                            ::aws_smithy_xml::decode::try_data(&mut tag)?.as_ref()
                            .into()
                        )
                        ?
                    )
                ;
                builder = builder.set_value(var_6);
            }
            ,
            _ => {}
        }
    }
    Ok(builder.build())
}