public Metrics reporter(final BiFunction<MetricRegistry, Config, Reporter> callback) {
    this.reporters.add(requireNonNull(callback, "Callback is required."));
    return this;
  }
public Metrics reporter(final BiFunction<MetricRegistry, Config, Reporter> callback) {
    this.reporters.add(requireNonNull(callback, "Callback is required."));
    return this;
  }
public Metrics reporter ( final BiFunction < MetricRegistry , Config , Reporter > callback ) { this . reporters . add ( requireNonNull ( callback , "Callback is required." ) ) ; return this ; }
Append a {@link Reporter} to the {@link MetricRegistry}.

@param callback Reporter callback.
@return This metrics module.
Append a { @link Reporter } to the { @link MetricRegistry } .