description

# register method Null safety

void register (

1. Metric metric

)

Register Metrics to make them visible to Observatory.

## Implementation

    static void register(Metric metric) {
      // TODO: When NNBD is complete, delete the following line.
      ArgumentError.checkNotNull(metric, 'metric');
      if (_metrics[metric.name] != null) {
        throw new ArgumentError('Registered metrics have unique names');
      }
      _metrics[metric.name] = metric;
    }