docs: public Observable<FirewallRuleInner> beginCreateOrUpdateAsync(String resourceGroupName, String serverName, String firewallRuleName, FirewallRuleInner parameters) {
          return beginCreateOrUpdateWithServiceResponseAsync(resourceGroupName, serverName, firewallRuleName, parameters).map(new Func1<ServiceResponse<FirewallRuleInner>, FirewallRuleInner>() {
              @Override
              public FirewallRuleInner call(ServiceResponse<FirewallRuleInner> response) {
                  return response.body();
              }
          });
      }