docs: void putCustomMetric(final DynatraceMetricDefinition customMetric) {
          try {
              httpClient.put(customMetricEndpointTemplate + customMetric.getMetricId() + "?api-token=" + config.apiToken())
                      .withJsonContent(customMetric.asJson())
                      .send()
                      .onSuccess(response -> {
                          logger.debug("created {} as custom metric in dynatrace", customMetric.getMetricId());
                          createdCustomMetrics.add(customMetric.getMetricId());
                      })
                      .onError(response -> {
                          if (logger.isErrorEnabled()) {
                              logger.error("failed to create custom metric {} in dynatrace: {}", customMetric.getMetricId(),
                                      response.body());
                          }
                      });
          } catch (Throwable e) {
              logger.error("failed to create custom metric in dynatrace: {}", customMetric.getMetricId(), e);
          }
      }