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: _s3_reference_data_source_description.rs
    path of file: ./repos/aws-sdk-rust/sdk/kinesisanalyticsv2/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>For a SQL-based Kinesis Data Analytics application, provides the bucket name and object key name that stores the reference data.</p>
#[non_exhaustive]
#[derive(::std::clone::Clone, ::std::cmp::PartialEq, ::std::fmt::Debug)]
pub struct S3ReferenceDataSourceDescription {
    /// <p>The Amazon Resource Name (ARN) o
    
    pub fn build(self) -> ::std::result::Result<crate::types::S3ReferenceDataSourceDescription, ::aws_smithy_types::error::operation::BuildError> {
        ::std::result::Result::Ok(crate::types::S3ReferenceDataSourceDescription {
            bucket_arn: self.bucket_arn.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "bucket_arn",
                    "bucket_arn was not specified but it is required when building S3ReferenceDataSourceDescription",
                )
            })?,
            file_key: self.file_key.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "file_key",
                    "file_key was not specified but it is required when building S3ReferenceDataSourceDescription",
                )
            })?,
            reference_role_arn: self.reference_role_arn,
        })
    }