Performance improvements

[Baraujo25]

This pull request introduces significant improvements to memory management and thread safety in the video streaming samplers, as well as enhancements to test coverage. The main updates include the ability to optionally release HTTP response data after processing to reduce memory usage, improved handling of playlist parsing, and new tests to ensure thread safety and correct behavior of these features.

Memory management and response data handling:

• Added new properties (hls.sampler.releaseSegmentResponseData, hls.sampler.releasePlaylistResponseData) to control whether segment and playlist HTTP response data are released after processing, reducing memory usage. Corresponding logic and helper methods were implemented in VideoStreamingSampler, and calls to release response data were added at appropriate points in both HLS and DASH samplers.

• Updated tests to verify that response data is correctly released when the new properties are enabled, and ensured test isolation by resetting property caches and environment setup.

Playlist and manifest parsing improvements:

• Improved playlist parsing in Playlist.java to only normalize line endings when necessary, avoiding unnecessary string replacements.

• In Manifest.java, introduced a shared, thread-safe MPDParser instance for DASH manifest parsing, and updated usage to improve efficiency and thread safety.

Test coverage and thread safety:

• Added comprehensive tests for concurrent parsing of DASH manifests to ensure thread safety of the shared parser instance, as well as tests for both static and dynamic manifest parsing.

Miscellaneous:

• Added necessary imports and setup in test files to support new features and maintain test reliability.

These changes collectively improve the efficiency, scalability, and reliability of the video streaming samplers in both production and test environments.