async fn create_db_parameter_group(
        &self,
        input: CreateDBParameterGroupMessage,
    ) -> Result<CreateDBParameterGroupResult, RusotoError<CreateDBParameterGroupError>> {
        let mut request = SignedRequest::new("POST", "rds", &self.region, "/");
        let params = self.new_params("CreateDBParameterGroup");
        let mut params = params;
        CreateDBParameterGroupMessageSerializer::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, CreateDBParameterGroupError::from_response)
            .await?;

        let mut response = response;
        let result = xml_util::parse_response(&mut response, |actual_tag_name, stack| {
            xml_util::start_element(actual_tag_name, stack)?;
            let result = CreateDBParameterGroupResultDeserializer::deserialize(
                "CreateDBParameterGroupResult",
                stack,
            )?;
            skip_tree(stack);
            xml_util::end_element(actual_tag_name, stack)?;
            Ok(result)
        })
        .await?;

        drop(response); // parse non-payload
        Ok(result)
    }
<p><p>Creates a new DB parameter group.</p> <p>A DB parameter group is initially created with the default parameters for the database engine used by the DB instance. To provide custom values for any of the parameters, you must modify the group after creating it using <i>ModifyDBParameterGroup</i>. Once you&#39;ve created a DB parameter group, you need to associate it with your DB instance using <i>ModifyDBInstance</i>. When you associate a new DB parameter group with a running DB instance, you need to reboot the DB instance without failover for the new DB parameter group and associated settings to take effect.</p> <important> <p>After you create a DB parameter group, you should wait at least 5 minutes before creating your first DB instance that uses that DB parameter group as the default parameter group. This allows Amazon Neptune to fully complete the create action before the parameter group is used as the default for a new DB instance. This is especially important for parameters that are critical when creating the default database for a DB instance, such as the character set for the default database defined by the <code>character<em>set</em>database</code> parameter. You can use the <i>Parameter Groups</i> option of the Amazon Neptune console or the <i>DescribeDBParameters</i> command to verify that your DB parameter group has been created or modified.</p> </important></p>
rusoto/services/neptune/src/generated.rs