Emmyzhou db/direct dataplane access

[emmyzhou-db]

What changes are proposed in this pull request?

Provide the readers and reviewers with the information they need to understand
this PR in a comprehensive manner.

Specifically, try to answer the two following questions:

• WHAT changes are being made in the PR? This should be a summary of the
  major changes to allow the reader to quickly understand the PR without having
  to look at the code.
• WHY are these changes needed? This should provide the context that the
  reader might be missing. For example, were there any decisions behind the
  change that are not reflected in the code itself?

The “why part” is the most important of the two as it usually cannot be
inferred from the code itself. A well-written PR description will help future
developers (including your future self) to know how to interact and update your
code.

How is this tested?

Describe any tests you have done; especially if test tests are not part of
the unit tests (e.g. local tests).

NO_CHANGELOG=true

[github-actions]

If integration tests don't run automatically, an authorized user can run them manually by following the instructions below:

Trigger:
go/deco-tests-run/sdk-java

Inputs:

• PR number: 448
• Commit SHA: f43141f6114a5d7bd4d5dcee4976b819f51a8af6

Checks will be approved automatically on success.