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: _test_mapping_output.rs
    path of file: ./repos/aws-sdk-rust/sdk/b2bi/src/operation/test_mapping
    
    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 TestMappingOutput {
    /// <p>Returns a string for the mapping that can be used to identify the mapping. Similar to a fingerprint</p>
    pub mapped_fi
    
    pub fn build(self) -> ::std::result::Result<crate::operation::test_mapping::TestMappingOutput, ::aws_smithy_types::error::operation::BuildError> {
        ::std::result::Result::Ok(crate::operation::test_mapping::TestMappingOutput {
            mapped_file_content: self.mapped_file_content.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "mapped_file_content",
                    "mapped_file_content was not specified but it is required when building TestMappingOutput",
                )
            })?,
            _request_id: self._request_id,
        })
    }