[bug]: InvalidOperationException: Collection was modified; enumeration operation may not execute.

[furoTmark]

Description

When running an indexing job for Algolia, we experience this an InvalidOperationException error intermittently.
The code is the following:

var batchResponses = await _client.SaveObjectsAsync(_indexName, dtos, cancellationToken: _token);
var taskResponses = new List<GetTaskResponse>();

foreach (var batchResponse in batchResponses)
{
    var taskResponse = await _client.WaitForTaskAsync(_indexName, batchResponse.TaskID, ct: _token);
    taskResponses.Add(taskResponse);
}

return taskResponses.Any(x => x.Status == TaskStatus.NotPublished);

From the stacktrace (that is added in the log output), it is an issue in the HttpRequestHeadersExtensions.Fill method probably comes from AlgoliaHttpRequester.SendRequestAsync line 70 ( httpRequestMessage.Headers.Fill(request.Headers); )

Client

Search

Version

7.4.1

Relevant log output

System.InvalidOperationException: Collection was modified; enumeration operation may not execute.
   at System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resource)
   at System.Collections.Generic.Dictionary`2.Enumerator.MoveNext()
   at Algolia.Search.Http.HttpRequestHeadersExtensions.Fill(HttpRequestHeaders headers, IDictionary`2 dictionary)
   at Algolia.Search.Http.AlgoliaHttpRequester.<SendRequestAsync>d__3.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Algolia.Search.Transport.HttpTransport.<ExecuteRequestAsync>d__10`2.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Algolia.Search.Transport.HttpTransport.<ExecuteRequestAsync>d__8`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Algolia.Search.Clients.SearchClient.<GetTaskAsync>d__72.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Algolia.Search.Clients.SearchClient.<>c__DisplayClass131_0.<<WaitForTaskAsync>b__0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Algolia.Search.Clients.SearchClient.<RetryUntil>d__149`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Algolia.Search.Clients.SearchClient.<WaitForTaskAsync>d__131.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at <<REDACTED>>.Algolia.AlgoliaIndexingJob.<CheckIfPublishedNotCompleted>d__55.MoveNext() in <<REDACTED>>
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at <<REDACTED>>.Algolia.AlgoliaIndexingJob.<IndexBatch>d__42.MoveNext() in <<REDACTED>>