SDK hangs when server is unreachable

Describe the bug I am using v3.9.1 and testing this against a local emulator.

I wanted to test how our code behaves in face of network partitions. Therefore, I reproduced a situation where the client is successfully initialized but before executing a transactional batch, the server is shut down. The result is that ExecuteAsync hangs.

To Reproduce

async Task Main()
{
    var connectionString = "AccountEndpoint=https://localhost:8081/;AccountKey=<account key>";
    
    var clientBuilder = new CosmosClientBuilder(connectionString);
    var clientWithSerialization = clientBuilder.WithSerializerOptions(new CosmosSerializationOptions
    {
        PropertyNamingPolicy = CosmosPropertyNamingPolicy.CamelCase
    });
    var containerProperties = new ContainerProperties
    {
        Id = "testcontainer",
        PartitionKeyPath = $"/partitionKey"
    };
    
    var client = clientWithSerialization.Build();
    var database = (await client.CreateDatabaseIfNotExistsAsync("test")).Database;
    var container = (await database.CreateContainerIfNotExistsAsync(containerProperties)).Container;
        
    var item = new Item
    {
        PartitionKey = "abc"
    };

    var batch = container.CreateTransactionalBatch(new PartitionKey(item.PartitionKey));
    batch.CreateItem(item);

    // Put a breakpoint here and before continuing, shut the server down
    var response = await batch.ExecuteAsync();
}

Expected behavior

• ExecuteAsync returns TransactionalBatchResponse where an error response status is indicated
• or an exception is thrown

Actual behavior ExecuteAsync never finishes.

Environment summary SDK Version: 3.9.1 OS Version: Windows

[skurik]

Thank you for the explanation @ealsur, makes sense.

[skurik]

Using gateway mode did not help.

It reproduces in a 4.7.2 console application: https://github.com/skurik/cosmos-hang