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: _forwarded_values.rs
    path of file: ./repos/aws-sdk-rust/sdk/cloudfront/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>This field is deprecated. We recommend that you use a cache policy or an origin request policy instead of this field.</p>
/// <p>If you want to include values in the cache key, use a cache policy. For more information, see <a href="https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/controlling-the-cache-key.html#cache-key-create-cache-policy">Creating cache policies</a> in the <i>Amazon 
    
    pub fn build(self) -> ::std::result::Result<crate::types::ForwardedValues, ::aws_smithy_types::error::operation::BuildError> {
        ::std::result::Result::Ok(crate::types::ForwardedValues {
            query_string: self.query_string.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "query_string",
                    "query_string was not specified but it is required when building ForwardedValues",
                )
            })?,
            cookies: self.cookies,
            headers: self.headers,
            query_string_cache_keys: self.query_string_cache_keys,
        })
    }