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: _worker_fleet.rs
    path of file: ./repos/aws-sdk-rust/sdk/iotroborunner/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.

/// A collection of workers organized within a facility.
#[non_exhaustive]
#[derive(::std::clone::Clone, ::std::cmp::PartialEq, ::std::fmt::Debug)]
pub struct WorkerFleet {
    /// Full ARN of the worker fleet.
    pub arn: ::std::string::String,
    /// Filters access by the worker fleet's identifier
    pub id: ::std::string::String,
    /// Human friendly name of the resource.
    pub name: ::std::string::String,
    /// Site ARN.
    pub site: ::std::string::String,
    /// Timestamp at which the resource was created.
    pub created_at: ::aws_smithy_types::DateTime,
    /// Timestamp at which the resource was last updated.
    pub updated_at: ::aws_smithy_types::DateTime,
    /// JSON blob containing additional fixed properties regarding the worker fleet
    pub additional_fixed_properties: ::std::option::Option<::std::string::String>,
}
impl WorkerFleet {
    /// Full ARN of the worker fleet.
    pub fn arn(&self) -> &str {
        use std::ops::Deref;
        self.arn.deref()
    }
    /// Filters access by the worker fleet's identifier
    pub fn id(&self) -> &str {
        use std::ops::Deref;
        self.id.deref()
    }
    /// Human friendly nam
    
    pub fn build(self) -> ::std::result::Result<crate::types::WorkerFleet, ::aws_smithy_types::error::operation::BuildError> {
        ::std::result::Result::Ok(crate::types::WorkerFleet {
            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 WorkerFleet",
                )
            })?,
            id: self.id.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "id",
                    "id was not specified but it is required when building WorkerFleet",
                )
            })?,
            name: self.name.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "name",
                    "name was not specified but it is required when building WorkerFleet",
                )
            })?,
            site: self.site.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "site",
                    "site was not specified but it is required when building WorkerFleet",
                )
            })?,
            created_at: self.created_at.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "created_at",
                    "created_at was not specified but it is required when building WorkerFleet",
                )
            })?,
            updated_at: self.updated_at.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "updated_at",
                    "updated_at was not specified but it is required when building WorkerFleet",
                )
            })?,
            additional_fixed_properties: self.additional_fixed_properties,
        })
    }