code: def test_buffer_stream(self):
      stream = Buffer(data=self.df, index=False)
      plot = self.df.hvplot("x", "y", stream=stream)
      pd.testing.assert_frame_equal(plot[()].data, self.df)
      new_df = pd.DataFrame([[7, 8], [9, 10]], columns=["x", "y"])
      stream.send(new_df)
      pd.testing.assert_frame_equal(
          plot[()].data, pd.concat([self.df, new_df])
      )
  
file_path: hvplot/hvplot/tests/teststreaming.py
imports: from unittest import TestCase
  import pandas
  from holoviews.streams import Buffer, Pipe
label_desc: Use image node_id 3 for calling the TestExplicitStreamPlotting obj's underlying member method code with example usage: obj.test_buffer_stream() without return types