import Piece from 'torrent-piece'

Piece.BLOCK_LENGTH // 16384

const pieceLength = Piece.BLOCK_LENGTH * 5
const piece = new Piece(pieceLength)
piece.missing // 81920

piece.reserve() // 0
piece.set(0, someBuffer0)

piece.reserve() // 1
piece.reserve() // 2
piece.reserve() // 3

piece.set(1, someBuffer1)
piece.set(2, someBuffer2)
piece.set(3, someBuffer3)

piece.reserve() // 4
piece.cancel(4) // cancel the reservation of a chunk

piece.reserve() // 4 (given out again)
piece.set(4, someBuffer4)

// handy functions
piece.chunkLength(0) // 16384
piece.chunkOffset(0) // 0

// eventually, when no more chunks left...

piece.reserve() // -1 (signal that all chunks are reserved)
piece.missing // 0

const pieceBuffer = piece.flush()
console.log(pieceBuffer)