code: def test_metrics_pusher_multiple_tasks():
      start = 0
      timer = MockTimer(start)
  
      with patch("time.time", new=timer.time), patch(
          "time.sleep", new=timer.realistic_sleep
      ):
          counter = {"A": 0, "B": 0, "C": 0}
          result = {}
          expected_results = {"A": 35, "B": 14, "C": 10}
  
          def task(key, c, res):
              time.sleep(0.001)
              c[key] += 1
              # Check for how many times this task has been called
              # At 7 seconds, tasks A, B, C should have executed 35, 14, and 10
              # times respectively.
              if timer.time() >= 7 and key not in res:
                  res[key] = c[key]
  
          metrics_pusher = MetricsPusher()
          # Each task interval is different, and they don't divide each other.
          metrics_pusher.register_task(
              lambda: task("A", counter, result), 0.2
          )
          metrics_pusher.register_task(
              lambda: task("B", counter, result), 0.5
          )
          metrics_pusher.register_task(
              lambda: task("C", counter, result), 0.7
          )
          metrics_pusher.start()
  
          # Check there are three results set and all are expected.
          def check_results():
              for key in result.keys():
                  assert result[key] == expected_results[key]
              assert len(result) == 3
              return True
  
          wait_for_condition(check_results, timeout=20)
  
imports: import asyncio
  import json
  import os
  import time
  from unittest.mock import patch
  import numpy
  import pytest
  from fastapi.encoders import jsonable_encoder
  import ray
  from ray import serve
  from ray._private.resource_spec import HEAD_NODE_RESOURCE_NAME
  from ray._private.test_utils import wait_for_condition
  from ray.serve._private.test_utils import MockTimer
  from ray.serve._private.utils import MetricsPusher, calculate_remaining_timeout, get_all_live_placement_group_names, get_current_actor_id, get_head_node_id, is_running_in_asyncio_loop, merge_dict, msgpack_deserialize, msgpack_serialize, override_runtime_envs_except_env_vars, serve_encoders, snake_to_camel_case
  from ray.serve.tests.common.remote_uris import TEST_DAG_PINNED_URI, TEST_DEPLOY_GROUP_PINNED_URI
label_desc: Use image node_id 13 for calling a global function with example usage: test_metrics_pusher_multiple_tasks() and returns: True