What is `sync.Pool` and how does it optimize memory?

sync.Pool is a thread-safe cache for reusing temporary objects, reducing memory allocations and Garbage Collection pressure.

When an application frequently allocates short-lived objects (like byte buffers for network I/O), the GC has to work hard to sweep them. sync.Pool caches these allocated objects. You Get() an object, use it, and Put() it back. If the pool is empty, it calls an allocation function. Note: The GC periodically clears sync.Pool, so it shouldn't hold long-lived state.