[INLONG-5258][SDK] DataProxy SDK(cpp) core interface

[pocozh]

Prepare a Pull Request

(Change the title refer to the following example)

• [INLONG-5258][SDK] DataProxy SDK(cpp) core interface

(The following XYZ should be replaced by the actual GitHub Issue number)

• Fixes [Feature][SDK] Add core interface for DataProxy C++ SDK  #5258

Motivation

Explain here the context, and why you're making that change. What is the problem you're trying to solve?

Modifications

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Verifying this change

(Please pick either of the following options)

• This change is a trivial rework/code cleanup without any test coverage.

• This change is already covered by existing tests, such as:
  (please describe tests)

• This change added tests and can be verified as follows:

  (example:)

  • Added integration tests for end-to-end deployment with large payloads (10MB)
  • Extended integration test for recovery after broker failure

Documentation

• Does this pull request introduce a new feature? (yes / no)
• If yes, how is the feature documented? (not applicable / docs / JavaDocs / not documented)
• If a feature is not applicable for documentation, explain why?
• If a feature is not documented yet in this PR, please create a follow-up issue for adding the documentation