[Bug] Jest detects open handle

cd activities-examples
npm run jest -- -t httpWorkflow

results in:

A worker process has failed to exit gracefully and has been force exited. This is likely caused by tests leaking due to improper teardown. Try running with --detectOpenHandles to find leaks. Active timers can also cause this, ensure that .unref() was called on them.

npm run jest -- -t httpWorkflow --detectOpenHandles

results in:

Jest has detected the following 1 open handle potentially keeping Jest from exiting:

  ●  neon threadsafe function

    > 1 | import { TestWorkflowEnvironment } from '@temporalio/testing';
        | ^
      2 | import { Worker, Runtime, DefaultLogger, LogEntry } from '@temporalio/worker';
      3 | import { v4 as uuid4 } from 'uuid';
      4 | import { httpWorkflow } from './workflows';

      at Object.<anonymous> (node_modules/@temporalio/worker/src/worker.ts:95:8)
      at Object.<anonymous> (node_modules/@temporalio/worker/src/index.ts:29:1)
      at Object.<anonymous> (node_modules/@temporalio/testing/src/index.ts:20:1)
      at Object.<anonymous> (src/workflows.test.ts:1:1)