# System.Diagnostics.Metrics

``` diff
 namespace System.Diagnostics.Metrics {
     public sealed class Counter<T> : Instrument<T> where T : struct {
+        public void Add(T delta, in TagList tagList);
     }
     public sealed class Histogram<T> : Instrument<T> where T : struct {
+        public void Record(T value, in TagList tagList);
     }
     public abstract class Instrument<T> : Instrument where T : struct {
+        protected void RecordMeasurement(T measurement, in TagList tagList);
     }
 }
```

