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: _rate_limit_query_string.rs
    path of file: ./repos/aws-sdk-rust/sdk/wafv2/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>Specifies the request's query string as an aggregate key for a rate-based rule. Each distinct string contributes to the aggregation instance. If you use just the query string as your custom key, then each string fully defines an aggregation instance.</p>
#[non_exhaustive]
#[derive(::std::clone::Clone, ::std::cmp::Part
    
    pub fn build(self) -> ::std::result::Result<crate::types::RateLimitQueryString, ::aws_smithy_types::error::operation::BuildError> {
        ::std::result::Result::Ok(crate::types::RateLimitQueryString {
            text_transformations: self.text_transformations.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "text_transformations",
                    "text_transformations was not specified but it is required when building RateLimitQueryString",
                )
            })?,
        })
    }