/**
   * Computes m (total bits of Bloom filter) which is expected to achieve, for the specified
   * expected insertions, the required false positive probability.
   *
   * <p>See http://en.wikipedia.org/wiki/Bloom_filter#Probability_of_false_positives for the
   * formula.
   *
   * @param n expected insertions (must be positive)
   * @param p false positive rate (must be 0 < p < 1)
   */
  @VisibleForTesting