code: def __init__(self, queue, block_size):
      self.queue = queue
      self.host_buf = np.empty(block_size, dtype=np.uint8)
      self.dev_buf = cl.Buffer(
          queue.context, cl.mem_flags.READ_WRITE, block_size
      )
  
imports: import pyopencl
  import numpy
label_desc: Use image node_id 1 to create a new HostDeviceTransferBase object  with example: obj = HostDeviceTransferBase(queue, block_size)