code: public ConsulResponse<List<ServiceHealth>> getHealthyServicesByDatacenterAndTag(final String serviceName,
                                                                                      final String datacenter,
                                                                                      final String tag) {
          return getHealthyServices(serviceName, datacenter, tag, RequestOptions.BLANK);
      }
docs: Retrieves the healthchecks for all healthy nodes in a given datacenter.
  <p>
  <code>GET /v1/health/service/{service}?dc={datacenter}&amp;passing</code>
  
  @param serviceName The service to query.
  @param datacenter  datacenter
  @param tag         tag
  @return A {@link io.advantageous.consul.domain.ConsulResponse} containing a list of
  {@link io.advantageous.consul.domain.HealthCheck} objects.