Emit 'start', 'done', and 'error' events for downloaded objects.

[mikenikles]

Relates to #39.

This PR emits the following events:

• start: When the download process for an object starts.
• done: When an object has been synced downloaded.
• error: When an error occurred.

Each event payload contains an object with:

• filePath: The path of the processed file.
• error: An Error in case of the error event.

Note: #39 also asks for ignore events. This PR does not include that. Happy to add that, but I would need some pointers as to where the best place for that is.

[jeanbmar]

Thank you for submitting a PR! Sounds like a great addition, I'll review it asap.

[jeanbmar]

Sorry for the late reply, I wanted to finish the ts migration before reviewing the PR.

In order to support the events, we need to have them for the following operations:

• CopyBucketObjectCommand
• DownloadBucketObjectCommand
• UploadLocalObjectCommand
• UploadLocalObjectsCommand for multipart uploads (+ remove logic from UploadLocalObjectPartCommand)
• DeleteBucketObjectsCommand since it probably makes sense to track delete operations too
• A new DeleteLocalObjectsCommand to be created (logic currently happening here)

If we are implementing an event for ignored objects, it needs to be emitted in:

• SyncLocalWithBucketCommand
• SyncBucketWithBucketCommand
• SyncBucketWithLocalCommand The isIncluded getter from SyncObject can be used for this.

We should probably change the naming a bit to avoid possible confusion between global transfer events and object events (e.g. start: objectStart)

Implementation is not hard from a technical perspective, but changes happen in a lot of commands. If you are still up to work on this that's great, else I can make the changes, let me know :).

Thanks!

[mikenikles]

No problem, I just caught up on the changes you've made and am excited to give the newest version a go! Looking at your detailed explanation, I believe you'd be much quicker to apply these changes given your familiarity with the code.

Having said that, do let me know when you have it ready for testing and I can test it. Your library is a core piece to how the https://indexed.xyz CLI works, so thank you for keeping it maintained 😍!