azure-sdk-for-net: [QUESTION] EventBatch doesn't clear after being sent

Describe the bug When sending multiple messages through the eventBatch helper, it doesn’t clear out after the batch is submitted. I have a 5MB payload to send to the hub. I break the payload in many smaller messages and loop through them, adding them up to the eventBatch until it gets close to 1MB. Then I invoke producerClient.SendAsync() to submit the batch and resume the loop for the next collection of messages. eventBatch doesn’t zero out and the loop tries to resubmit the same batch. The eventBatch.SizeInBytes still shows the already submitted payload.

Expected behavior After invoking producerClient.SendAsync(eventBatch) I expect to get a clean batch to start filling up with new messages.

Actual behavior (include Exception or Stack Trace) The eventBatch does not clear out. It is of no use in a loop to send a payload larger than 1MB.

To Reproduce A slightly modified version of the sample official sample:

` public static void trySendingMultipleBatches() { { // Create a producer client that you can use to send events to an event hub await using (var producerClient = new EventHubProducerClient(connectionString, eventHubName)) { // Create a batch of events using EventDataBatch eventBatch = await producerClient.CreateBatchAsync();

        // Try 3 batches 
        for (int i = 0; i < 3; i++)
        {

            while (eventBatch.SizeInBytes < 800000)
            {
                // Add events to the batch. An event is a represented by a collection of bytes and metadata. 
                eventBatch.TryAdd(new EventData(Encoding.UTF8.GetBytes("First event")));
                eventBatch.TryAdd(new EventData(Encoding.UTF8.GetBytes("Second event")));
                eventBatch.TryAdd(new EventData(Encoding.UTF8.GetBytes("Third event")));
            }
            // Use the producer client to send the batch of events to the event hub
            await producerClient.SendAsync(eventBatch);
            Console.WriteLine("A batch of about 1MB has been published.");
        }
    }
}

}

`

Environment:

• Azure.Messaging.EventHubs 5.2.0

• Hosting platform or OS and .NET runtime version (dotnet --info) .NET Core SDK (reflecting any global.json): Version: 3.1.300 Commit: b2475c1295

Runtime Environment: OS Name: Windows OS Version: 10.0.18363 OS Platform: Windows RID: win10-x64 Base Path: C:\Program Files\dotnet\sdk\3.1.300\

Host (useful for support): Version: 3.1.4 Commit: 0c2e69caa6

.NET Core SDKs installed: 3.1.300 [C:\Program Files\dotnet\sdk]

.NET Core runtimes installed: Microsoft.AspNetCore.All 2.1.18 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.App 2.1.18 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 3.1.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.NETCore.App 2.1.18 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 3.1.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.WindowsDesktop.App 3.1.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

• Visual Studio Code Version: 1.50.1 (user setup) Commit: d2e414d9e4239a252d1ab117bd7067f125afd80a Date: 2020-10-13T15:06:15.712Z Electron: 9.2.1 Chrome: 83.0.4103.122 Node.js: 12.14.1 V8: 8.3.110.13-electron.0 OS: Windows_NT x64 10.0.18363