Any tool that has right click functionality (Bow or sword, not fishing rod though) can be used to "pause" the breaking of a block and to later break it fully if no other blocks have been touched. (Tested in survival only)
To reproduce:
Get out a sword
Hold right click to block
Hold left click to start destroying a block (Something with a long break time such as stone)
Let go of both left and right click
The breaking overlay stays in place and can be resumed as long as no other block has been touched.
To resume the breaking of the block, hold right click again and then left click on the same block and it will continue the break animation until the block is broken.
(Sacrificed my hardcore world to take these screenshots! </3 lol)
Dupe of MC-64066