async fn add_tags_to_resource(
        &self,
        input: AddTagsToResourceMessage,
    ) -> Result<(), RusotoError<AddTagsToResourceError>> {
        let mut request = SignedRequest::new("POST", "rds", &self.region, "/");
        let params = self.new_params("AddTagsToResource");
        let mut params = params;
        AddTagsToResourceMessageSerializer::serialize(&mut params, "", &input);
        request.set_payload(Some(serde_urlencoded::to_string(&params).unwrap()));
        request.set_content_type("application/x-www-form-urlencoded".to_owned());

        let response = self
            .sign_and_dispatch(request, AddTagsToResourceError::from_response)
            .await?;

        std::mem::drop(response);
        Ok(())
    }
<p>Adds metadata tags to an Amazon Neptune resource. These tags can also be used with cost allocation reporting to track cost associated with Amazon Neptune resources, or used in a Condition statement in an IAM policy for Amazon Neptune.</p>
rusoto/services/neptune/src/generated.rs