code: public Observable<CredentialResultsInner> listClusterUserCredentialsAsync(String resourceGroupName, String resourceName) {
          return listClusterUserCredentialsWithServiceResponseAsync(resourceGroupName, resourceName).map(new Func1<ServiceResponse<CredentialResultsInner>, CredentialResultsInner>() {
              @Override
              public CredentialResultsInner call(ServiceResponse<CredentialResultsInner> response) {
                  return response.body();
              }
          });
      }
docs: Gets cluster user credential of a managed cluster.
  Gets cluster user credential of the managed cluster with a specified resource group and name.
  
  @param resourceGroupName The name of the resource group.
  @param resourceName The name of the managed cluster resource.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the CredentialResultsInner object