@Override
  public void setCompilationStartStamp(@NotNull Collection<? extends BuildTarget<?>> targets, long stamp) {
    synchronized (myCompilationStartStamp) {
      for (BuildTarget<?> target : targets) {
        myCompilationStartStamp.put(target, stamp);
      }
    }
  }
@Override
  public void setCompilationStartStamp(@NotNull Collection<? extends BuildTarget<?>> targets, long stamp)