Sharing `Events<T>` between `World`s

## What problem does this solve or what need does it fill?

There are many cases where `World`s need to share `Events`.
Examples:
- sending events to another world to process them, then recover the result
- sending events across network ( from @alice-i-cecile )

## Proposed solutions

### Solution 1
Add `Clone` trait to `Events`.

Pros:
- Easy to implement

Cons:
- Cloned resource won't send events properly

### Solution 2
Use some sort of MPSC to send & receive events with thread-safety.

Pros:
- Easy to implement

Cons:
- Would need to be implemented in `Events` or would require a custom `ThreadSafeEvents`
- Has low performance

The issue names no file, test, or entry point. First resolve whether Events should be cloned or transferred through an MPSC, then define the chosen scope; done means events can be sent between Worlds and the result recovered, including the network case if it is included.

Written by the indexing model from the issue text.