Update Startup.cs with Kafka and namespace changes

Modified `using` directives to include additional namespaces: `System.Net.Sockets`, `System.Xml.Linq`, and `static System.Runtime.InteropServices.JavaScript.JSType`. Changed Kafka broker address from `localhost` to `127.0.0.1`. Added a commented PowerShell script for running a Kafka Docker container with detailed configuration. Expanded context in `Sample.Kafka.PostgreSql` namespace with additional comments and code.

Fix RabbitMQ consuming body reusing (#1727)

* Fix rabbitMQ consuming body reusing

* ArrayPool for memory management

* Rollback to simply array copy

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Co-authored-by: Pavel Dudnikov <[email protected]>

Enhance error handling in delay message sending process. (#1367)

Improved error handling and logging during message sending.
Wrapped `_sender.SendAsync(nextMessage)` in a try-catch block to log errors with message IDs.

Update version to 8.3.4

Update apperyor api_key

do not throw exception for existing cap-msg-group message header. ove…

…rwrite it instead. tolerate kafka message duplicate headers (#1623)

Fixes RabbitMQ transport reject function call error. (#1608)

Add more default retryable error codes for Kakfa consumption exceptio…

…ns. #1587

Tweak that when the `EnablePublishParallelSend` option is true, it wi…

…ll be put task into the .NET thread pool in batches rather than all at once. (#1540)

Fixed an issue where the PublishDelay synchronization method did not …

…wait internally.