anchor.diff:  ----
   
   ==== @Gauge
  -An annotation for marking a method as a gauge.
  +An annotation for marking a method as a gauge. No default `MetricUnit` is supplied, so the `unit` must always be specified explicitly.
   
   The implementation must support the following annotation target:
   
  
positive.code: .Example of an annotated method
  [source, java]
  ----
  @Gauge
  public long getValue() {
    return value;
  }
  
negative.code: .Example set-up of a Gauge metric.  No unit is given, so `MetricUnits.NONE` is used, an explicit name is provided
  [source,java]
  ----
  @Gauge(unit = MetricUnits.NONE, name = "queueSize")
  public int getQueueSize() {
    return queue.size;
  }
  