Added Stream as Export Attribute Macro

[chavic]

Summary

• Enhanced Stream Support:

  • Supported various stream types and tested with simple streams, count streams, Fibonacci streams, and combined streams as seen in tests.
  • Enabled handling of custom data types and error-producing streams.
  • Updated generate_object with a new generate_stream method and macros which also incorporates Finalizer usage.
  • Removed manual drop() methods from Dart stream generators.
  • Added an optional dispose() method for manual resource management when necessary.
  • Verified normal stream emissions.
  • Tested error-producing streams.
  • Ensured proper resource cleanup.
  • Validated stream cancellation behavior.

• Implemented Lifecycle Management:

  • Integrated Dart's Finalizer to automatically manage the disposal of Rust stream objects.
  • Prevented segmentation faults by eliminating premature drop() calls in Dart.

Fixes

• Resolved Segmentation Faults:

  • Addressed crashes caused by premature disposal of Rust stream objects by leveraging Finalizer.

• Prevented Memory Leaks:

  • Ensured Rust objects are properly freed after stream usage through automated lifecycle management.

Next Steps

• Expose Additional Rust Functions:

  • Implement get_drop_counter() to monitor and verify resource cleanup in Dart tests.

• Enhance FFI Converters:

  • Fully support complex data types and error handling between Rust and Dart.

Please review the changes and let me know if there are any adjustments