Macro counter 

macro_rules! counter {
    ($name:literal : $value:expr $(, $tag:literal => $tv:expr)* $(,)?) => { ... };
}

Emits a counter metric.

Syntax

use objectstore_metrics::counter;

counter!("name": 1u64);
counter!("name": 1u64, "tag" => "value");
counter!("name": 1u64, "tag1" => "val1", "tag2" => "val2");