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: _retrieve_output.rs
    path of file: ./repos/aws-sdk-rust/sdk/bedrockagentruntime/src/operation/retrieve
    
    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)]
pub struct RetrieveOutput {
    /// <p>A list of results from querying the knowledge base.</p>
    pub retrieval_results: ::std::vec::Vec<crate::types::KnowledgeBaseRetrievalResult>,
    /// <p>If there are more results than can fit in the response, the response returns a <code>nextToken</code>. Use this token 
    
    pub fn build(self) -> ::std::result::Result<crate::operation::retrieve::RetrieveOutput, ::aws_smithy_types::error::operation::BuildError> {
        ::std::result::Result::Ok(crate::operation::retrieve::RetrieveOutput {
            retrieval_results: self.retrieval_results.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "retrieval_results",
                    "retrieval_results was not specified but it is required when building RetrieveOutput",
                )
            })?,
            next_token: self.next_token,
            _request_id: self._request_id,
        })
    }