code: def start_sample_client(rank, tmpdir, disable_shared_mem):
      gpb = None
      if disable_shared_mem:
          _, _, _, gpb, _, _, _ = load_partition(
              tmpdir / "test_sampling.json", rank
          )
      dgl.distributed.initialize("rpc_ip_config.txt")
      dist_graph = DistGraph("test_sampling", gpb=gpb)
      try:
          sampled_graph = sample_neighbors(
              dist_graph, [0, 10, 99, 66, 1024, 2008], 3
          )
      except Exception as e:
          print(traceback.format_exc())
          sampled_graph = None
      dgl.distributed.exit_client()
      return sampled_graph
  
imports: import multiprocessing
  import os
  import random
  import sys
  import time
  import traceback
  import unittest
  from pathlib import Path
  import backend
  import dgl
  import numpy
  import pytest
  from dgl.data import CitationGraphDataset, WN18Dataset
  from dgl.distributed import DistGraph, DistGraphServer, load_partition, load_partition_book, partition_graph, sample_etype_neighbors, sample_neighbors
  from scipy import sparse
  from utils import generate_ip_config, reset_envs
label_desc: Use image node_id 2 for calling a global function with example usage: start_sample_client(rank, tmpdir, disable_shared_mem) and returns: sampled_graph