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: _list_apps_output.rs
    path of file: ./repos/aws-sdk-rust/sdk/resiliencehub/src/operation/list_apps
    
    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(missing_docs)] // documentation missing in model
#[non_exhaustive]
#[derive(::std::clone::Clone, ::std::cmp::PartialEq, ::std::fmt::Debug)]
pub struct ListAppsOutput {
    /// <p>Summaries for the Resilience Hub application.</p>
    pub app_summaries: ::std::vec::Vec<crate::types::AppSummary>,
    /// <p>Token for the next set of results, or null if there are no more results.</p>
    pub next_token: ::std::option::O
    
    pub fn build(self) -> ::std::result::Result<crate::operation::list_apps::ListAppsOutput, ::aws_smithy_types::error::operation::BuildError> {
        ::std::result::Result::Ok(crate::operation::list_apps::ListAppsOutput {
            app_summaries: self.app_summaries.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "app_summaries",
                    "app_summaries was not specified but it is required when building ListAppsOutput",
                )
            })?,
            next_token: self.next_token,
            _request_id: self._request_id,
        })
    }