Currently if a buffer from the buffer is too small to satisfy its request then we simply drop it and allocate a new one.
This change puts it back in the pool and then allocates a new one.
The current bytes.Pool will hold onto byte slices indefinitely. Large
writes can cause the pool to hold onto very large buffers over time.
Testing w/ sync/pool seems to perform similarly now so using a sync/pool
will allow these buffers to be GC'd when necessary.
This allows encoders to be re-used and maintained in a pool to
avoid allocating new ones on every compactions and write of an encoded
block. The pool used is not a sync.Pool to ensure that the encoders
will not be garbage collected.
Carlo Alberto Ferraris
Jason Wilder
Edd Robinson
Hrvoje Marjanovic
Ben Johnson