anchor.diff:  
   `Histogram` is a complex metric type comprised of multiple key/values. Each key will require a suffix to be appended to the metric name with appropriate naming/scaling based on <<prometheus_units>>.  The format is specified by the table below.
   
  -The `# HELP` description line is only required for the `count` value as shown below.
  +The `# HELP` description line is only required for the `summary` value as shown below.
   
   .Prometheus text mapping for a Histogram metric
   [cols="2,1,2,1"]
   |===
   | Suffix{label}                   | TYPE    | Value (Histogram method)            | Units
   
  -| `count`                         | Counter | `getCount()`                        | N/A
   | `min_<units>`                   | Gauge   | `getSnapshot().getMin()`            | <units>^1^
   | `max_<units>`                   | Gauge   | `getSnapshot().getMax()`            | <units>^1^
   | `mean_<units>`                  | Gauge   | `getSnapshot().getMean()`           | <units>^1^
   | `stddev_<units>`                | Gauge   | `getSnapshot().getStdDev()`         | <units>^1^
  +| `<units>_count`^2^              | Summary | `getCount()`                        | N/A
   | `<units>{quantile="0.5"}`^2^    | Summary | `getSnapshot().getMedian()`         | <units>^1^
   | `<units>{quantile="0.75"}`^2^   | Summary | `getSnapshot().get75thPercentile()` | <units>^1^
   | `<units>{quantile="0.95"}`^2^   | Summary | `getSnapshot().get95thPercentile()` | <units>^1^
  
positive.code: 
  ^1^ The implementation is expected to convert the result returned by the `Timer` into seconds
  
  ^2^ The `summary` type is a complex metric type for Prometheus which consists of multiple quantile values.
  
  .Example Prometheus text format for a Timer
  [source, ruby]
  ----
  # TYPE application:response_time_count counter
  # HELP application:response_time_count Server response time for /index.html
  application:response_time_count 80
  # TYPE application:response_time_rate_per_second gauge
  application:response_time_rate_per_second  0.004292520715985437
  # TYPE application:response_time_one_min_rate_per_second gauge
  
negative.code: # TYPE application:file_sizes_stddev_bytes gauge
  application:file_sizes_stddev_bytes 1054.7343037063602
  # TYPE application:file_sizes_bytes summary
  # HELP application:file_sizes_bytes Users file size
  application:file_sizes_bytes_count 2037
  application:file_sizes_bytes{quantile="0.5"} 4201
  application:file_sizes_bytes{quantile="0.75"} 6175
  application:file_sizes_bytes{quantile="0.95"} 13560
  