Macro try_call_return_response 

macro_rules! try_call_return_response {
    (@output_msg $handle: expr, $status_code: expr) => { ... };
    ($handle: expr, $status_code: expr) => { ... };
    ($handle: expr) => { ... };
}

Helper macro which try to evaluate the expression and return its results. If the evaluation fails, return a PrometheusJsonResponse early.