for p := binary.MaxVarintLen64; p < size; n++ {
		x, w := binary.Uvarint(buf[p:])
		data.set(n, int64(x))
		p += w
	}

	return
}

const bufSize = 16 << 10 // reasonable for BenchmarkSaveRestore

// Read reads the index from r into x; x must not be nil.
func (x *Index) Read(r io.Reader) error {
	// buffer for all reads
	buf := make([]byte, bufSize)

	// read length

							b.SetBytes(int64(len(data)))
							b.ReportAllocs()
							for i := 0; i < b.N; i++ {
								New(data)
							}
						})
					}
				})
			}
		})
	}
}

func BenchmarkSaveRestore(b *testing.B) {
	r := rand.New(rand.NewSource(0x5a77a1)) // guarantee always same sequence
	data := make([]byte, 1<<20)             // 1MB of data to index
	for i := range data {
		data[i] = byte(r.Intn(256))
	}