Ability to configure reader buffer threshold

[vgvoleg]

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

Closes: #442

What is the new behavior?

Other information

[Copilot]

Pull request overview

Adds a configurable buffer release threshold to the Topic reader so the client can batch “freed buffer” notifications (ReadRequests) to reduce round-trips.

Changes:

• Exposes buffer_release_threshold on TopicClient.reader(...) (async + sync) and documents it.
• Adds PublicReaderSettings.buffer_release_threshold with [0.0, 1.0] validation.
• Implements accumulated buffer release + adds unit/integration tests.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
ydb/topic.py	Exposes buffer_release_threshold in public reader factory methods.
ydb/_topic_reader/topic_reader.py	Adds setting + validates threshold range in PublicReaderSettings.
ydb/_topic_reader/topic_reader_asyncio.py	Accumulates released bytes and sends ReadRequest when threshold is reached or queue empties.
ydb/_topic_reader/topic_reader_asyncio_test.py	Adds unit tests for threshold behavior + validation.
tests/topics/test_topic_reader.py	Adds async + sync integration tests to ensure the new parameter works end-to-end.
docs/topic.rst	Documents the new parameter semantics and provides an example.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated no new comments.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 4 comments.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.