Add Async Socket Connection and Writing with Fiber Refactor

Why it matters

This feature addresses the inefficiencies in synchronous connection handling and query sending across shards by enabling asynchronous operations. It reduces latency and improves resource utilization during distributed query execution. Additionally, it lays the groundwork for safely increasing the default connect_timeout_with_failover_ms value, enhancing connection reliability.

How to use it

The asynchronous connection and socket writing behavior is integrated internally; users benefit automatically when running distributed queries involving shards. To take full advantage, ensure your ClickHouse version includes this update. No explicit user configuration is required to enable async connections, but monitoring and adjusting connect_timeout_with_failover_ms after upgrade is recommended.