5 Write data into it, and it'll output data in buffer blocks the size you
6 specify, padding with zeroes if necessary.
9 var block = new BlockStream(512)
10 fs.createReadStream("some-file").pipe(block)
11 block.pipe(fs.createWriteStream("block-file"))
14 When `.end()` or `.flush()` is called, it'll pad the block with zeroes.