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: _app_bundle.rs
    path of file: ./repos/aws-sdk-rust/sdk/appfabric/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>Contains information about an app bundle.</p>
#[non_exhaustive]
#[derive(::std::clone::Clone, ::std::cmp::PartialEq, ::std::fmt::Debug)]
pub struct AppBundle {
    /// <p>The Amazon Resource Name (ARN) of the app bundle.</p>
    pub arn: ::std::string::String,
    /// <p>The Amazon Resource Name (ARN) of the Key Management Service (
    
    pub fn build(self) -> ::std::result::Result<crate::types::AppBundle, ::aws_smithy_types::error::operation::BuildError> {
        ::std::result::Result::Ok(crate::types::AppBundle {
            arn: self.arn.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "arn",
                    "arn was not specified but it is required when building AppBundle",
                )
            })?,
            customer_managed_key_arn: self.customer_managed_key_arn,
        })
    }