Running BlockBlobClient highlevel unit test with t2 Azure Storage SDK has an socket issue

Azurite Version: v3.8.0

Issue Description:
Run BlockBlobClient highlevel unit test with t2 Azure Storage SDK In Azurite, an socket issue is shown in the figure below:
Note: If disable keep alive when create blob service client, the socket issue will not happen. The modified code snippet is as following:
```typescript
const serviceClient = new BlobServiceClient(
baseURL,
newPipeline(
new StorageSharedKeyCredential(
EMULATOR_ACCOUNT_NAME,
EMULATOR_ACCOUNT_KEY
),
{
retryOptions: { maxTries: 1 },
// Make sure socket is closed once the operation is done.
keepAliveOptions: { enable: false }
}
)
);
```

Steps to reproduce:
1)Clone the repo from [link](https://github.com/zzhxiaofeng/Azurite.git).
2)Open Azurite folder with VS Code and run command `npm i` to install dependencies packages.
3)Run command `npm run test` to run all unit test.

Note: it does not happen at every time, it happens at some time. Please try more times.

Expected Behavior:
Run highlevel unit test successfully.