[MC-858] Server lag in singleplayer

Moderator Note

"Block lag" is not a bug, it is a symptom of one of myriad causes. There are multiple things you can try:
• Turn down your render distance (to 8 or lower)
• Turn VBOs "on" in video settings
• Make sure you don't have any possibly lag causing things, like too many entities
• Update your graphics card drivers
• Give Minecraft more RAM (with regular resource pack, 2 GB is enough)
• Upgrade your hardware

When the player is clearing blocks and clears one or two blocks they are instantaneously regenerated after those blocks were cleared. The same happens when placing blocks, they disappear for a while at first.

The internal server is having low TPS and therefore registering the block-breaking action from the client very late. This leads to the client re-displaying the block again, until it gets the confirmation from the server that its actually broken, seconds later, or not at all. At the end, the block is either broken or still there, on both client and server.