macro_rules! record_stats {
(info | $($stmt:stmt);+;) => { ... };
(gauge set | $ident:ident | $amount:expr) => { ... };
(gauge inc | $ident:ident | $amount:expr) => { ... };
(gauge dec | $ident:ident | $amount:expr) => { ... };
(counter set | $ident:ident | $amount:expr) => { ... };
(counter inc | $ident:ident | $amount:expr) => { ... };
(counter dec | $ident:ident | $amount:expr) => { ... };
(observe | $ident:ident | $amount:expr) => { ... };
(time_hist | $ident:ident | $block:block) => { ... };
}