code: public ProcessExecutor redirectInput(InputStream input) {
      PumpStreamHandler pumps = pumps();
      // Only set the input stream handler, preserve the same output and error stream handler
      return streams(new PumpStreamHandler(pumps == null ? null : pumps.getOut(), pumps == null ? null : pumps.getErr(), input));
    }
docs: Sets the input stream to redirect to the process' input stream.
  If this method is invoked multiple times each call overwrites the previous.
  
  @param input input stream that will be written to the process input stream (<code>null</code> means nothing will be written to the process input stream).
  @return This process executor.