# File lib/rubytorrent/peer.rb, line 21
  def to_bitstring
    ret = "\0"
    bit = 7
    map do |b|
      if bit == -1
        ret += "\0"
        bit = 7
      end
      ret[ret.length - 1] |= (1 << bit) if b
      bit -= 1
    end
    ret
  end