Macro count 

macro_rules! count {
    ($stat:expr, $count:expr) => { ... };
    ($stat:path, $count:expr) => { ... };
    ($stat:expr, $count:expr; $( $key:literal => $value:literal ), *) => { ... };
    ($stat:path, $count:expr; $( $key:literal => $value:literal ), *) => { ... };
    ($stat:expr, $count:expr; $( $key:expr => $value:expr ), *) => { ... };
    ($stat:path, $count:expr; $( $key:expr => $value:expr ), *) => { ... };
}

Make an arbitrary change to a StatsD counter NOTE: Try to minimise variation in tag values (avoid things like timestamps or ids). See note in lib docs!