Scheduling & performance

[TobiX]

Currently, dosage downloads comic in a very straightforward way:

1. Get page
2. Parse page
3. Get images
4. Continue with next page

For better performance, the user can decide to run download multiple comics in parallel (via the -p option) - but that's more of a clutch - the threads aren't aware of each other, which could lead to the situation where multiple threads fetch comics from the same hoster.

We should evaluate a better scheduling system, satisfying at least the following requirements:

• [ ] Parallel downloads from multiple hosts
• [ ] Throttling per host (we don't want to overload a hoster)
• [ ] Image downloads can be handled separate from page parsing

It might be worthwhile to look at things like asyncio, async/await or something like that...