
  [;1m-spec bit_size(Bitstring) -> non_neg_integer()[0m
  [;1m                  when Bitstring :: bitstring().[0m

  Returns an integer that is the size in bits of [;;4mBitstring[0m, for
  example:

    > bit_size(<<433:16,3:3>>).
    19
    > bit_size(<<1,2,3>>).
    24

  Allowed in guard tests.
