TemporaryBuffer is great when the output size is not known, but must
be bound by a relatively large upper limit that fits in memory, e.g.
64 KiB or 20 MiB. The buffer gracefully supports growing storage by
allocating 8 KiB blocks and storing them in an ArrayList.
In a Git repository many deltas are less than 8 KiB. Typical tree
objects are well below this threshold, and their deltas must be
encoded even smaller.
For these much smaller cases avoid the 8 KiB minimum allocation used
by TemporaryBuffer. Instead allocate a very small OutputStream
writing to an array that is sized at the limit.