code: public List<Long> searchBigFile(File f, byte[] searchBytes, OnProgressListener listener) {
  
  		this.onRealtimeResultListener = null;
  		this.onProgressListener = listener;
  
  		int numOfThreadsOptimized = (int) (f.length() / (long) blockSize);
  
  		if (numOfThreadsOptimized == 0) {
  			numOfThreadsOptimized = 1;
  		}
  
  		return searchBigFile(f, searchBytes, numOfThreadsOptimized, this.useOptimization, 0);
  	}
docs: Search bytes from big file faster in a concurrent processing with
  progress callback
  
  @param f
  target file
  @param searchBytes
  sequence of bytes you want to search
  @param listener
  callback for progress
  @return