code: def read(self, size: int):
      # we read cuda_header first and then read cuda buffers one by one,
      # the return value's size is not exactly the specified size.
      from cudf.core.buffer import Buffer
      from cupy.cuda import MemoryPointer
      from cupy.cuda.memory import UnownedMemory
  
      if not self._has_read_headers:
          self._has_read_headers = True
          return pickle.dumps(self._headers)
      if len(self._buffers) == 0:
          return ""
      cur_buf = self._buffers[0]
      # current buf read to end
      if cur_buf is None:
          # empty cuda buffer
          content = Buffer.empty(0)
          self._offset = 0
          self._buffers.pop(0)
          return content
      elif size >= cur_buf.size - self._offset:
          if isinstance(cur_buf, UnownedMemory):
              cupy_pointer = MemoryPointer(cur_buf, self._offset)
              content = Buffer(
                  cupy_pointer.ptr, size=cur_buf.size - self._offset
              )
          else:
              content = cur_buf[self._offset : self._offset + size]
          self._offset = 0
          self._buffers.pop(0)
          return content
      else:
          if isinstance(cur_buf, UnownedMemory):
              cupy_pointer = MemoryPointer(cur_buf, self._offset)
              self._offset += size
              return Buffer(cupy_pointer.ptr, size=size)
          else:
              self._offset += size
              return cur_buf[self._offset, self._offset + size]
  
imports: import ctypes
  import pickle
  import uuid
  from io import BytesIO
  from typing import Tuple, Dict, List, Union
  from ..serialization import serialize, deserialize
  from ..utils import lazy_import, implements
  from .base import StorageBackend, StorageLevel, ObjectInfo, register_storage_backend
  from .core import StorageFileObject
  import numpy
  import pandas
label_desc: Use image node_id 6 for calling the CudaFileObject obj's underlying member method code with example usage: obj.read(size) and returns: pickle, str, content, content, Buffer, cur_buf