RFR: 8229517: Support for optional asynchronous/buffered logging [v19]

[Xin Liu]

> This patch provides a buffer to store asynchrounous messages and flush them to
> underlying files periodically.

Xin Liu has updated the pull request incrementally with one additional commit since the last revision:

  Update according to reviewers' feedback (Part-2).

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/3135/files
  - new: https://git.openjdk.java.net/jdk/pull/3135/files/2381ba19..cad42d79

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=3135&range=18
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=3135&range=17-18

  Stats: 67 lines in 5 files changed: 29 ins; 10 del; 28 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3135.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3135/head:pull/3135

PR: https://git.openjdk.java.net/jdk/pull/3135