// is 128 then the mask is 127 == 0x7f, keeping the bottom 7 bits of the hash value.
  // If a key hashes to 0x89abcdef the mask reduces it to 0x89abcdef & 0x7f == 0x6f. We'll call this
  // the "short hash".
  //
  // The `keys`, `values`, and `entries` arrays always have the same size as each other. They can be
  // seen as fields of an imaginary `Entry` object like this:
  //

  // is 128 then the mask is 127 == 0x7f, keeping the bottom 7 bits of the hash value.
  // If a key hashes to 0x89abcdef the mask reduces it to 0x89abcdef & 0x7f == 0x6f. We'll call this
  // the "short hash".
  //
  // The `keys`, `values`, and `entries` arrays always have the same size as each other. They can be
  // seen as fields of an imaginary `Entry` object like this:
  //