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: _avail_matching_criteria.rs
    path of file: ./repos/aws-sdk-rust/sdk/mediatailor/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>MediaTailor only places (consumes) prefetched ads if the ad break meets the criteria defined by the dynamic variables. This gives you granular control over which ad break to place the pref
    
    pub fn build(self) -> ::std::result::Result<crate::types::AvailMatchingCriteria, ::aws_smithy_types::error::operation::BuildError> {
        ::std::result::Result::Ok(crate::types::AvailMatchingCriteria {
            dynamic_variable: self.dynamic_variable.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "dynamic_variable",
                    "dynamic_variable was not specified but it is required when building AvailMatchingCriteria",
                )
            })?,
            operator: self.operator.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "operator",
                    "operator was not specified but it is required when building AvailMatchingCriteria",
                )
            })?,
        })
    }