[FLINK-30189] HsSubpartitionFileReader may load data that has been consumed from memory

[reswqa]

What is the purpose of the change

In order to solve the problem that data cannot be read from the disk correctly after failover, we changed the calculation logical of the buffer's readable state in FLINK-29238. Buffers that are greater than consumingOffset and have been released can be pre-load from file. However, the update of consumingOffset is asynchronous, If it lags behind the actual consumption progress, the buffer will have a chance to be load from the disk again.

Brief change log

• HsSubpartitionFileReaderImpl will skip peek buffer that less than expected.

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): no
• The public API, i.e., is any changed class annotated with @Public(Evolving): no
• The serializers: no
• The runtime per-record code paths (performance sensitive): no
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: no
• The S3 file system connector: no

Documentation

• Does this pull request introduce a new feature? no

[flinkbot]

CI report:

• b3cd214 Azure: SUCCESS

Bot commands

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[xintongsong]

Thanks @reswqa. LGTM. I have one minor comment, which I'll address myself during merging.

[xintongsong]

Suggested change

	return peek == null ? Optional.empty() : Optional.of(peek);
	return Optional.ofNullable(peek);