[FLINK-13326] Support asynchronous writing to raw operator (and raw keyed) state

[igalshilman]

What is the purpose of the change

Currently, the users of the AbstractStreamOperator class, are expected to complete the writing of rawKeyedOperatorState and rawOperatorState in the synchronous part of a snapshot (before the completion of snapshotState method)
But sometimes it is desirable to snapshot a custom data structure asynchronously (i.e. out side of the snapshotState method) in a similar way that the other state backends allow.

This PR adds the ability to suspend the closing of the raw states streams in snapshotState outside of the snapshotState method, and hence effectively support async snapshots for raw states.

Flink snapshotting logic already supports splitting the snapshot to sync and async parts for the various state backends, therefore the changes introduced in this PR mainly reuse that logic.

Brief change log

• Add an interruptible close method to ResourceGuard (the default is still unInterruptible).
• Add and use a ResourceGuard in NonClosingCheckpointOutputStream.
• modify the StateSnapshotContextSynchronousImpl#getRaw*OperatorStateOutput to return a future that completes after all the leases were released.

Verifying this change

This change is already covered by existing tests.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): (yes / no)
• The public API, i.e., is any changed class annotated with @Public(Evolving): (yes / no)
• The serializers: (yes / no / don't know)
• The runtime per-record code paths (performance sensitive): (yes / no / don't know)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Yarn/Mesos, ZooKeeper: (yes / no / don't know)
• The S3 file system connector: (yes / no / don't know)

Documentation

• Does this pull request introduce a new feature? (yes / no)
• If yes, how is the feature documented? (not applicable / docs / JavaDocs / not documented)

[flinkbot]

Thanks a lot for your contribution to the Apache Flink project. I'm the @flinkbot. I help the community
to review your pull request. We will use this comment to track the progress of the review.

Automated Checks

Last check on commit 27108b5 (Tue Aug 06 15:44:29 UTC 2019)

Warnings:

• No documentation files were touched! Remember to keep the Flink docs up to date!

_{Mention the bot in a comment to re-run the automated checks.}

Review Progress

• ❓ 1. The [description] looks good.
• ❓ 2. There is [consensus] that the contribution should go into to Flink.
• ❗ 3. Needs [attention] from.
  • Needs attention by @StefanRRichter
• ❓ 4. The change fits into the overall [architecture].
• ❓ 5. Overall code [quality] is good.

Please see the Pull Request Review Guide for a full explanation of the review process.

The Bot is tracking the review progress through labels. Labels are applied according to the order of the review items. For consensus, approval by a Flink committer of PMC member is required

Bot commands

The @flinkbot bot supports the following commands:

• @flinkbot approve description to approve one or more aspects (aspects: description, consensus, architecture and quality)
• @flinkbot approve all to approve all aspects
• @flinkbot approve-until architecture to approve everything until architecture
• @flinkbot attention @username1 [@username2 ..] to require somebody's attention
• @flinkbot disapprove architecture to remove an approval you gave earlier

[igalshilman]

@flinkbot attention @StefanRRichter

[flinkbot]

CI report:

• 27108b5 : SUCCESS Build

[StefanRRichter]

Thanks for your contribution @igalshilman ! Changes look good to me, just tell me if/when you would like to have them merged to master :-)

[igalshilman]

@StefanRRichter thanks! I'm ok with merging it.