def metainfoCompletedLength
      num = @completePieces.countSet
      # Last block may be smaller
      extra = 0
      if @completePieces.set?(@completePieces.length-1)
        num -= 1
        extra = @lastPieceLength
      end
      num*BlockSize + extra
    end
def metainfoCompletedLength
      num = @completePieces.countSet
      # Last block may be smaller
      extra = 0
      if @completePieces.set?(@completePieces.length-1)
        num -= 1
        extra = @lastPieceLength
      end
      num*BlockSize + extra
    end
Return the number of bytes of the metainfo that we have downloaded so far.