code: public Observable<SharedAccessAuthorizationRuleListResultInner> listKeysAsync(String resourceGroupName, String namespaceName, String authorizationRuleName) {
          return listKeysWithServiceResponseAsync(resourceGroupName, namespaceName, authorizationRuleName).map(new Func1<ServiceResponse<SharedAccessAuthorizationRuleListResultInner>, SharedAccessAuthorizationRuleListResultInner>() {
              @Override
              public SharedAccessAuthorizationRuleListResultInner call(ServiceResponse<SharedAccessAuthorizationRuleListResultInner> response) {
                  return response.body();
              }
          });
      }
docs: Gets the Primary and Secondary ConnectionStrings to the namespace.
  
  @param resourceGroupName The name of the resource group.
  @param namespaceName The namespace name.
  @param authorizationRuleName The connection string of the namespace for the specified authorizationRule.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the SharedAccessAuthorizationRuleListResultInner object