code: protected void rehash(KType[] fromKeys) {
      assert HashContainers.checkPowerOfTwo(fromKeys.length - 1);
  
      // Rehash all stored keys into the new buffers.
      final KType[] keys = Intrinsics.<KType[]> cast(this.keys);
      final int mask = this.mask;
      KType existing;
      for (int i = fromKeys.length - 1; --i >= 0;) {
        if (!Intrinsics.isEmpty(existing = fromKeys[i])) {
          int slot = hashKey(existing) & mask;
          while (!Intrinsics.isEmpty(keys[slot])) {
            slot = (slot + 1) & mask;
          }
          keys[slot] = existing;
        }
      }
    }
docs: Rehash from old buffers to new buffers.