code: public ConfigurationProviderBuilder withMetrics(MetricRegistry metricRegistry, String prefix) {
      this.prefix = requireNonNull(prefix);
      this.metricRegistry = metricRegistry;
      return this;
    }
docs: Enable metrics emission for {@link ConfigurationProvider}s built by this builder. All metrics will be registered
  with {@code metricRegistry} and prefixed by {@code prefix}. Provider built by this builder will emit the following metrics:
  <p>Provider-level metrics:</p>
  <ul>
  <li>allConfigurationAsProperties</li>
  <li>getProperty</li>
  <li>getPropertyGeneric</li>
  <li>bind</li>
  </ul>
  <p>Source-level metrics</p>
  <ul>
  <li>source.getConfiguration</li>
  <li>source.init</li>
  <li>source.reload</li>
  </ul>
  Each of those metrics is of {@link Timer} type (i.e. includes execution time percentiles, execution count, etc.)
  
  @param metricRegistry metric registry for registering metrics
  @param prefix         prefix for metric names
  @return this builder