How to reset the player's block breaking progress with a client-side forge mod?

I want to reset the player's block breaking progress at an arbitrary point in time, but I cannot cancel the block breaking event itself, as that is against the rules of the server I will use my mod on. 

mc.playerController.resetBlockRemoving();

only works 1/3rd of the time and i have no idea why. 

KeyBinding.setKeyBindState(mc.gameSettings.keyBindAttack.getKey() , false);

and then waiting 0.5 seconds (ideally i want to wait much less) and then 

KeyBinding.setKeyBindState(mc.gameSettings.keyBindAttack.getKey() , true);

also works 1/3rd of the time. please help. I have been stuck for a couple of hours.