Craft the bridger with 5 cobblestone, a lava and water bucket, one redstone dust, and a piston.
Using the lava and water contained in the bridger, it will generate and place cobblestone in the direction its facing when placed.
The direction is not limited to cardinal; you can place it upwards or downwards, and in water or in lava.
It stops when its chunk gets unloaded, or if there is a block in its way. It will resume when that block is cleared.
See my other mods