Function rest_reward_state_service_get_reward_balance 

async fn rest_reward_state_service_get_reward_balance<S>(
    __arg0: State<Arc<S>>,
    headers: HeaderMap,
    __arg2: Query<GetRewardBalanceRequest>,
) -> Result<Json<RewardBalanceResponse>, RestError>
where
    S: RewardStateService + Send + Sync + 'static,

GetRewardBalance - JSON endpoint.

GET /v2/merklized-state/reward/balance