Drupal 8.x

Hi I've created a module with a controller but now i'm getting this message;

LogicException: The controller result claims to be providing relevant cache metadata, but leaked metadata was detected. Please ensure you are not rendering content too early. Returned object class: Drupal\Core\Cache\CacheableJsonResponse. in Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext() (line 154 of core\lib\Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber.php).

Hi

I have created some custom blocks. Everytime I change the content I need to rebuild caches. Is this default behaviour or something weird in my set up?

If other users enter the content, the block does not update until I rebuild cache.

Is there anyway to clear the block cache automatically when the block is saved?

Hi Guys, 

This cache_clear_all function is no more in D8 whats the actual replacement for this ? 

I want the actual replacement, In D7 I'm using this function as :

cache_clear_all($cid, 'cache_API_NAME_api', TRUE);

to clear the cache from the api. 

I want the function which will work similar to this. 

Note: I had tried drupal_flush_all_caches() as a replacement of this but it is only clearing the Drupal cache not from the api.