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: _create_user_output.rs
    path of file: ./repos/aws-sdk-rust/sdk/transfer/src/operation/create_user
    
    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 CreateUserOutput {
    /// <p>The identifier of the server that the user is attached to.</p>
    pub server_id: ::std::string::String,
    /// <p>A unique string that identifies a Transfer Family user.</p>
    pub user_name: ::std::string::String,
    _request_id: Option<String>,
}
impl CreateUserOutput {
    /// <p>The identifier of the server that the user is attached to.</p>
    pub fn server_id(&self) -> &str {
        use s
    
    pub fn build(self) -> ::std::result::Result<crate::operation::create_user::CreateUserOutput, ::aws_smithy_types::error::operation::BuildError> {
        ::std::result::Result::Ok(crate::operation::create_user::CreateUserOutput {
            server_id: self.server_id.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "server_id",
                    "server_id was not specified but it is required when building CreateUserOutput",
                )
            })?,
            user_name: self.user_name.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "user_name",
                    "user_name was not specified but it is required when building CreateUserOutput",
                )
            })?,
            _request_id: self._request_id,
        })
    }