Expected Behavior

If I set the difficulty to easy/normal/hard, my player should recover half a heart every 4 seconds.
If I set the difficulty to peaceful, my player should still receive the recovery above on top of the peaceful natural regeneration.
If the server is a hardcore world, I should not regenerate health naturally.

Actual Behavior

There is no implementation of naturally regenerating your hearts on difficulties higher than peaceful. This causes a desync in health causing the client to display more health than they actually have. (the client regenerates health even if you don't send the update attribute packet)

Steps to Reproduce

• Set the difficulty to a difficulty above peaceful in your server.properties
• Damage yourself
• Ensure that you have full hunger.
• It will appear that you have regenerated clientside. However, if you take damage it will revert back to the health the server says you have.

Debug information

• Debug link:
• Timings link (if relevant):

Crashdump, Backtrace or Other Files

Checklist:

• [] I included a /debugpaste link
• I made sure there aren't duplicates of this report (Use Search)
• I made sure I am using an up-to-date version of Nukkit
• I Made sure the bug/error is not caused by a plugin