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: _tag.rs
    path of file: ./repos/aws-sdk-rust/sdk/kinesisvideo/src/types
    
    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.

/// <p>A key and value pair that is associated with the specified signaling channel.</p>
#[non_exhaustive]
#[derive(::std::clone::Clone, ::std::cmp::PartialEq, ::std::fmt::Debug)]
pub struct Tag {
    /// <p>The key of the tag that is associated with the specified signaling channel.</p>
    pub key: ::std::string::String,
    /// <p>The value of the tag that is associated with the specified signaling channel.</p>
    pub value: ::std::string::String,

    
    pub fn build(self) -> ::std::result::Result<crate::types::Tag, ::aws_smithy_types::error::operation::BuildError> {
        ::std::result::Result::Ok(crate::types::Tag {
            key: self.key.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field("key", "key was not specified but it is required when building Tag")
            })?,
            value: self.value.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "value",
                    "value was not specified but it is required when building Tag",
                )
            })?,
        })
    }