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