feat: add buffer pool

[tiennampham23]

No description provided.

[eitu5ami]

@tiennampham23 Thank you for your contribution! Could you provide some context behind this change?

[tiennampham23]

@eitu5ami I apologize for missing the description earlier. The buffer pool is used to prevent the allocation of a large number of byte slices when uploading a significant amount of data. We utilize the allocated buffer pool to store the response bytes.

If we do not use the buffer pool, the reserve proxy will allocate the byte slices with every request, and the garbage collection will clear it afterward. As the number of requests increases, the memory usage will peak at the time the garbage collector is running.

As the documentation

// BufferPool optionally specifies a buffer pool to
// get byte slices for use by io.CopyBuffer when
// copying HTTP response bodies.
BufferPool BufferPool



if p.BufferPool != nil {
   buf = p.BufferPool.Get()
   defer p.BufferPool.Put(buf)
}

[eitu5ami]

@tiennampham23 I will work on it once I merge a few of our outstanding changes. I will keep you posted.