Macro dipstick::metrics

macro_rules! metrics {
    ($(#[$attr:meta])* pub $IDENT:ident: $TYPE:ty = $e:expr => { $($BRANCH:tt)*} $($REST:tt)*) => { ... };
    ($(#[$attr:meta])* $IDENT:ident: $TYPE:ty = $e:expr => { $($BRANCH:tt)* } $($REST:tt)*) => { ... };
    ($(#[$attr:meta])* pub $IDENT:ident = $e:expr => { $($BRANCH:tt)* } $($REST:tt)*) => { ... };
    ($(#[$attr:meta])* $IDENT:ident = $e:expr => { $($BRANCH:tt)* } $($REST:tt)*) => { ... };
    ($e:ident => { $($BRANCH:tt)+ } $($REST:tt)*) => { ... };
    ($e:expr => { $($BRANCH:tt)+ } $($REST:tt)*) => { ... };
    ($(#[$attr:meta])* pub $IDENT:ident: $TYPE:ty = $e:expr; $($REST:tt)*) => { ... };
    ($(#[$attr:meta])* $IDENT:ident: $TYPE:ty = $e:expr; $($REST:tt)*) => { ... };
    () => { ... };
    (@internal $WITH:expr; $TY:ty; $(#[$attr:meta])* pub $IDENT:ident: $MTY:ty = $METRIC_NAME:expr; $($REST:tt)*) => { ... };
    (@internal $WITH:expr; $TY:ty; $(#[$attr:meta])* $IDENT:ident: $MTY:ty = $METRIC_NAME:expr; $($REST:tt)*) => { ... };
    (@internal $WITH:expr; $TY:ty; $(#[$attr:meta])* pub $IDENT:ident = $e:expr => { $($BRANCH:tt)*} $($REST:tt)*) => { ... };
    (@internal $WITH:expr; $TY:ty; $(#[$attr:meta])* $IDENT:ident = $e:expr => { $($BRANCH:tt)*} $($REST:tt)*) => { ... };
    (@internal $WITH:expr; $TY:ty; $(#[$attr:meta])* pub $e:expr => { $($BRANCH:tt)*} $($REST:tt)*) => { ... };
    (@internal $WITH:expr; $TY:ty; $(#[$attr:meta])* $e:expr => { $($BRANCH:tt)*} $($REST:tt)*) => { ... };
    (@internal $WITH:expr; $TYPE:ty;) => { ... };
}

Metrics can be used from anywhere (public), does not need to declare metrics in this block.