While the new Buffer implementation is much faster we still have the
necessity of using Buffer pools. This is undesirable because it may
still lead to unwanted memory retention, but for the time being this is
the best solution.
Because of this re-introduction, and since there is no more SlowBuffer
type, the SlowBuffer method has been re-purposed to return a non-pooled
Buffer instance. This will be helpful for developers to store data for
indeterminate lengths of time without introducing a memory leak.
Another change to Buffer pools was that they are only allocated if the
requested chunk is < poolSize / 2. This was done because allocations are
much quicker now, and it's a better use of the pool.