This module defines a type for mutable, integer-valued counters. Counters are non-negative, monotonically increasing values and can be used to track e.g. the number of requests served since program start. All operations on counters 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.Counter module from the ekg-core package instead.