piece

type Manager interface {
	//SetPeerPieces associates remote peer and pieces it possess
	SetPeerPieces(peerID string, pieces []bool)
	//PieceSize returns size of a piece corresponding to given index,
	//often last piece has different size than preceding pieces.
	PieceSize(index uint32) uint32
	ChunkSize() uint32
	//Get retrieves piece corresponding to given index
	Get(index uint32) (pieceData []byte, err error)
	//PieceDone saves piece in the storage
	PieceDone(index uint32, pieceData []byte) error
	//NextPiece checks if peers has more pieces to offer.
	// (false, 0) -> peer has no more pieces
	// (true, index) -> index is the next piece index to request
	NextPiece(peerID string) (hasNext bool, index uint32)
	//IsLastChunk checks if the whole piece was downloaded
	IsLastChunk(pieceIndex, offset uint32) bool
}

type Repository interface {
	Save(piece uint32, data []byte) error
	Get(piece uint32) ([]byte, error)
}