David Turner b21cb7f466 Reduce allocations when persisting cluster state (#61159)
Today we allocate a new `byte[]` for each document written to the
cluster state. Some of these documents may be quite large. We need a
buffer that's at least as large as the largest document, but there's no
need to use a fresh buffer for each document.

With this commit we re-use the same `byte[]` much more, only allocating
it afresh if we need a larger one, and using the buffer needed for one
round of persistence as a hint for the size needed for the next one.
2020-08-17 13:45:31 +01:00
..