[Discussion] Adding BufferManager and ThreadPool utilities

- BufferManager: A centralized mechanism to manage memory buffers efficiently, particularly in scenarios involving high-frequency data processing, streaming, or caching, also control the memory usage and deal with user provided memory.
- ThreadPool: A reusable pool of threads to manage task execution and improve concurrency without overwhelming system resources.

没有指定源文件、测试或入口点。首先阅读 issue 讨论并调研仓库架构，以确定缓冲区管理和线程池工具应归属的位置。在开始实现之前，应根据已达成一致的范围、API、资源行为和验证计划来定义“Done”。

由索引模型根据 Issue 内容生成。