code: public ServiceFuture<List<ManagedInstanceKeyInner>> listByInstanceAsync(final String resourceGroupName, final String managedInstanceName, final String filter, final ListOperationCallback<ManagedInstanceKeyInner> serviceCallback) {
          return AzureServiceFuture.fromPageResponse(
              listByInstanceSinglePageAsync(resourceGroupName, managedInstanceName, filter),
              new Func1<String, Observable<ServiceResponse<Page<ManagedInstanceKeyInner>>>>() {
                  @Override
                  public Observable<ServiceResponse<Page<ManagedInstanceKeyInner>>> call(String nextPageLink) {
                      return listByInstanceNextSinglePageAsync(nextPageLink);
                  }
              },
              serviceCallback);
      }
docs: Gets a list of managed instance keys.
  
  @param resourceGroupName The name of the resource group that contains the resource. You can obtain this value from the Azure Resource Manager API or the portal.
  @param managedInstanceName The name of the managed instance.
  @param filter An OData filter expression that filters elements in the collection.
  @param serviceCallback the async ServiceCallback to handle successful and failed responses.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceFuture} object