public void beforeNextRoundStart(@NotNull CompileContext context, ModuleChunk chunk) {
    FilesDelta currentDelta = getRoundDelta(NEXT_ROUND_DELTA_KEY, context);
    if (currentDelta == null) {
      // this is the initial round.
      // Need to make a snapshot of the FS state so that all builders in the chain see the same picture
      final List<FilesDelta> deltas = new SmartList<>();
      for (ModuleBuildTarget target : chunk.getTargets()) {
        deltas.add(getDelta(target));
      }
      currentDelta = new FilesDelta(deltas);
    }
    setRoundDelta(CURRENT_ROUND_DELTA_KEY, context, currentDelta);
    setRoundDelta(NEXT_ROUND_DELTA_KEY, context, new FilesDelta());
  }
public void beforeNextRoundStart(@NotNull CompileContext context, ModuleChunk chunk)