Currently when you click a block, voxel-clientmc will call mineflayer's dig() method, which handles starting and stopping digging. So you only need to hit it once, then mining will occur after it is complete, regardless of whether you continue mining. What should happen is when the player starts mining, it sends block_dig with digging start, and block_dig with digging stop when the player stops, so that if you do not fully mine the block client-side, is it not mined server-side.
Currently when you click a block, voxel-clientmc will call mineflayer's dig() method, which handles starting and stopping digging. So you only need to hit it once, then mining will occur after it is complete, regardless of whether you continue mining. What should happen is when the player starts mining, it sends block_dig with digging start, and block_dig with digging stop when the player stops, so that if you do not fully mine the block client-side, is it not mined server-side.