This module defines a type for mutable, integer-valued gauges. Gauges are variable values and can be used to track e.g. the current number of concurrent connections. All operations on gauges are thread-safe.
N.B. This module exists to maintain backwards compatibility with
older versions of this library. New code should use the
System.Metrics.Gauge module from the ekg-core package instead.
A mutable, integer-valued gauge.