Enhancements for fs-index Crate

[tareknaser]

This is a tracking issue for brainstorming ideas to enhance fs-index crate

• ResourceIndex exposed API should be as discussed here Refactor the API for ResourceIndex arklib#91 (comment)
• id_to_resources should be of type HashMap<HashType, Vec<IndexedResource>> instead of HashMap<ResourceId, CanonicalPathBuf> because one id can map to multiple resource in case of collisions or same content
• Revise ResourceIndex::update() to rebuild the index and compare with the old index. Benchmarking for this feature should be conducted as per issue Enhance Benchmarking Suite and Add Profiling Support #30.
• Implement file system watch and update index functionality as described in fs-index: Filesystem monitoring using notify-rs #21.

The difference between watch_index and ark-cli monitor is that watch_index uses notify to only update the index when a file system change is detected, as opposed to rebuilding the index from scratch on a time interval.

• Create examples folder:
  • Include one example showing the normal scenario of creating a new index in a specified path and using the API.
  • Include another example showcasing index watch functionality.
• Benchmark the performance of resource indexing queries and operations as outlined in issue Enhance Benchmarking Suite and Add Profiling Support #30.
• Ensure that modules are private and only necessary structs and methods are exported.
• Place unit tests in a separate file instead of index.rs.
• Implement a custom Serialize implementation for ResourceIndex where double mappings are not written.

[tareknaser]

@kirillt

I think we can safely close this issue now. Is there anything else related to this you'd like to suggest we do first?

[kirillt]

It seems that all sub-issues have been addressed.

Great work, thanks!