chore: close streams

[caalador]

touches #12489

[github-actions]

Unit Test Results

   720 files     720 suites   21m 19s ⏱️
5 648 tests 5 598 ✔️ 50 💤 0 ❌
5 659 runs  5 609 ✔️ 50 💤 0 ❌

Results for commit b197b5c.

♻️ This comment has been updated with latest results.

[Artur-]

CRITICAL StreamReceiverHandler.java#L29: Remove this unused import 'java.io.UncheckedIOException'. rule

[vaadin-bot]

SonarQube analysis reported 5 issues

1. FeatureFlags.java#L1: Class com.vaadin.experimental.FeatureFlags defines non-transient non-serializable instance field lookup
2. FeatureFlags.java#L63: Make "lookup" transient or serializable.
3. FeatureFlags.java#L77: Remove this call from a constructor to the overridable "loadProperties" method.
4. FeatureFlags.java#L121: "context" is a method parameter, and should not be used for synchronization.
5. StreamReceiverHandler.java#L554: Method has 8 parameters, which is greater than 7 authorized.

[vaadin-bot]

Hi @caalador and @caalador, when i performed cherry-pick to this commit to 2.8, i have encountered the following issue. Can you take a look and pick it manually?
Error Message:
Error: Command failed: git cherry-pick 62eeb17
error: could not apply 62eeb17... chore: close streams (#12491)
hint: after resolving the conflicts, mark the corrected paths
hint: with 'git add ' or 'git rm '
hint: and commit the result with 'git commit'

[vaadin-bot]

Hi @caalador and @caalador, when i performed cherry-pick to this commit to 2.7, i have encountered the following issue. Can you take a look and pick it manually?
Error Message:
Error: Command failed: git cherry-pick 62eeb17
error: could not apply 62eeb17... chore: close streams (#12491)
hint: after resolving the conflicts, mark the corrected paths
hint: with 'git add ' or 'git rm '
hint: and commit the result with 'git commit'