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: _staging_distribution_dns_names.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>The CloudFront domain name of the staging distribution.</p>
#[non_exhaustive]
#[derive(::std::clone::Clone, ::std::cmp::PartialEq, ::std::fmt::Debug)]
pub struct StagingDistributionDnsNames {
    /// <p>The number of CloudFront domain names in your staging distribu
    
    pub fn build(self) -> ::std::result::Result<crate::types::StagingDistributionDnsNames, ::aws_smithy_types::error::operation::BuildError> {
        ::std::result::Result::Ok(crate::types::StagingDistributionDnsNames {
            quantity: self.quantity.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "quantity",
                    "quantity was not specified but it is required when building StagingDistributionDnsNames",
                )
            })?,
            items: self.items,
        })
    }