@NotNull
  IntPair getCustomRegionsYAdjustment(int offset, int idx) {
    if (!isFoldingEnabled()) return new IntPair(0,0);
    CachedData cachedData = ensureAvailableData();
    int prevAdjustment = idx == -1 ? 0 : cachedData.topCustomYAdjustment[idx];
    int curAdjustment = idx + 1 < cachedData.topStartOffsets.length && cachedData.topStartOffsets[idx + 1] == offset
                        ? cachedData.topCustomYAdjustment[idx + 1] - prevAdjustment : 0;
    return new IntPair(prevAdjustment, curAdjustment);
  }
@NotNull
  IntPair getCustomRegionsYAdjustment(int offset, int idx)