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: _existing_object_replication.rs
    path of file: ./repos/aws-sdk-rust/sdk/s3/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>Optional configuration to replicate existing source bucket objects. For more information, see <a href="https://docs.aws.amazon.com/AmazonS3/latest/dev/replication-what-is-isnot-replicated.html#existing-object-replication">Replicating Existing Objects</a> in the <i>Amazon S3 User Guide</
    
    pub fn build(self) -> ::std::result::Result<crate::types::ExistingObjectReplication, ::aws_smithy_types::error::operation::BuildError> {
        ::std::result::Result::Ok(crate::types::ExistingObjectReplication {
            status: self.status.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "status",
                    "status was not specified but it is required when building ExistingObjectReplication",
                )
            })?,
        })
    }