code: def testBuffering(self):
      buf = MPI.Alloc_mem((1 << 16) + MPI.BSEND_OVERHEAD)
      MPI.Attach_buffer(buf)
      try:
          with self.catchNotImplementedError(4, 1):
              MPI.Flush_buffer()
          with self.catchNotImplementedError(4, 1):
              MPI.Iflush_buffer().Wait()
      finally:
          oldbuf = MPI.Detach_buffer()
          self.assertEqual(oldbuf.address, buf.address)
          self.assertEqual(oldbuf.nbytes, buf.nbytes)
          MPI.Free_mem(buf)
      if MPI.BUFFER_AUTOMATIC != 0:
          MPI.Attach_buffer(MPI.BUFFER_AUTOMATIC)
          bufauto = MPI.Detach_buffer()
          self.assertEqual(bufauto, MPI.BUFFER_AUTOMATIC)
  
file_path: mpi4py/test/test_buffer.py
imports: from mpi4py import MPI
  import mpiunittest
label_desc: Use image node_id 14 for calling the TestBuffer obj's underlying member method code with example usage: obj.testBuffering() without return types