f8.1/sdk/dart/package-fuchsia_inspect_inspect/DoubleProperty/add.md

# add method




    *[<Null safety>](https://dart.dev/null-safety)*




void add
(double delta)

_<span class="feature">inherited</span>_



<p>Adds <code>delta</code> to the value of this metric.</p>



## Implementation

```dart
void add(T delta) {
  _writer?.addMetric(index, delta);
}
```